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.TH "CMAKE-POLICIES" "7" "Mar 04, 2024" "3.29.0" "CMake"
.SH NAME
cmake-policies \- CMake Policies Reference
.SH INTRODUCTION
.sp
Policies in CMake are used to preserve backward compatible behavior
across multiple releases.  When a new policy is introduced, newer CMake
versions will begin to warn about the backward compatible behavior.  It
is possible to disable the warning by explicitly requesting the OLD, or
backward compatible behavior using the \fI\%cmake_policy()\fP command.
It is also possible to request \fBNEW\fP, or non\-backward compatible behavior
for a policy, also avoiding the warning.  Each policy can also be set to
either \fBNEW\fP or \fBOLD\fP behavior explicitly on the command line with the
\fI\%CMAKE_POLICY_DEFAULT_CMP<NNNN>\fP variable.
.sp
A policy is a deprecation mechanism and not a reliable feature toggle.
A policy should almost never be set to \fBOLD\fP, except to silence warnings
in an otherwise frozen or stable codebase, or temporarily as part of a
larger migration path. The \fBOLD\fP behavior of each policy is undesirable
and will be replaced with an error condition in a future release.
.sp
The \fI\%cmake_minimum_required()\fP command does more than report an
error if a too\-old version of CMake is used to build a project.  It
also sets all policies introduced in that CMake version or earlier to
\fBNEW\fP behavior.  To manage policies without increasing the minimum required
CMake version, the \fI\%if(POLICY)\fP command may be used:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
if(POLICY CMP0990)
  cmake_policy(SET CMP0990 NEW)
endif()
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
This has the effect of using the \fBNEW\fP behavior with newer CMake releases which
users may be using and not issuing a compatibility warning.
.sp
The setting of a policy is confined in some cases to not propagate to the
parent scope.  For example, if the files read by the \fI\%include()\fP command
or the \fI\%find_package()\fP command contain a use of \fI\%cmake_policy()\fP,
that policy setting will not affect the caller by default.  Both commands accept
an optional \fBNO_POLICY_SCOPE\fP keyword to control this behavior.
.sp
The \fI\%CMAKE_MINIMUM_REQUIRED_VERSION\fP variable may also be used
to determine whether to report an error on use of deprecated macros or
functions.
.SH POLICIES INTRODUCED BY CMAKE 3.29
.SS CMP0161
.sp
New in version 3.29.

.sp
The \fI\%CPACK_PRODUCTBUILD_DOMAINS\fP variable defaults to true.
.sp
Before CMake 3.29, the \fI\%CPACK_PRODUCTBUILD_DOMAINS\fP variable is
unset by default.  When using the \fI\%CPack productbuild Generator\fP,
this disables the use of the \fBdomains\fP attribute in the productbuild
Distribution XML, and falls back to the \fBauth\fP attribute instead.
These attributes control where a productbuild package is allowed to be
installed.  But the \fBauth\fP attribute has been deprecated by Apple,
so projects should migrate to using \fBdomains\fP instead.
.sp
CMake 3.29 and above prefer to use a default value of true for
\fI\%CPACK_PRODUCTBUILD_DOMAINS\fP, which means \fBdomains\fP will be used
by default unless the project explicitly sets
\fI\%CPACK_PRODUCTBUILD_DOMAINS\fP to false.
This policy provides compatibility with projects that enabled the
\fI\%CPack productbuild Generator\fP, but did not explicitly set
\fI\%CPACK_PRODUCTBUILD_DOMAINS\fP\&.
.sp
The \fBOLD\fP behavior for this policy is to leave
\fI\%CPACK_PRODUCTBUILD_DOMAINS\fP unset if it hasn\(aqt been set.
The \fBNEW\fP behavior for this policy is to use a default value of true for
\fI\%CPACK_PRODUCTBUILD_DOMAINS\fP\&.
.sp
This policy was introduced in CMake version 3.29\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
Note that a warning will only be emitted if the
\fI\%CPACK_BINARY_PRODUCTBUILD\fP variable is
set to true and the project is being built for an Apple platform.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0160
.sp
New in version 3.29.

.sp
More read\-only target properties now error when trying to set them.
.sp
The \fI\%set_target_properties()\fP and \fI\%set_property()\fP commands
are intended to error out on all read\-only properties. However, CMake 3.28 and
below only did this for the following properties:
.INDENT 0.0
.IP \(bu 2
\fI\%HEADER_SETS\fP
.IP \(bu 2
\fI\%INTERFACE_HEADER_SETS\fP
.IP \(bu 2
\fI\%IMPORTED_GLOBAL\fP
.IP \(bu 2
\fI\%MANUALLY_ADDED_DEPENDENCIES\fP
.IP \(bu 2
\fI\%NAME\fP
.IP \(bu 2
\fI\%TYPE\fP
.UNINDENT
.sp
This policy enforces the read\-only nature of the following target properties:
.INDENT 0.0
.IP \(bu 2
\fI\%ALIAS_GLOBAL\fP
.IP \(bu 2
\fI\%BINARY_DIR\fP
.IP \(bu 2
\fI\%CXX_MODULE_SETS\fP
.IP \(bu 2
\fI\%IMPORTED\fP
.IP \(bu 2
\fI\%INTERFACE_CXX_MODULE_SETS\fP
.IP \(bu 2
\fI\%LOCATION\fP
.IP \(bu 2
\fI\%LOCATION_<CONFIG>\fP
.IP \(bu 2
\fI\%SOURCE_DIR\fP
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to only error out for the properties
\fI\%MANUALLY_ADDED_DEPENDENCIES\fP, \fI\%NAME\fP, and \fI\%TYPE\fP\&.
The \fBNEW\fP behavior for this policy is to error out on all target properties
that are documented as read\-only.
.sp
This policy was introduced in CMake version 3.29\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0159
.sp
New in version 3.29.

.sp
\fI\%file(STRINGS)\fP with \fBREGEX\fP updates \fI\%CMAKE_MATCH_<n>\fP\&.
.sp
In CMake 3.28 and below the \fI\%file(STRINGS)\fP command\(aqs \fBREGEX\fP
option does not affect \fI\%CMAKE_MATCH_<n>\fP variables.  CMake 3.29
and above prefer to update the \fI\%CMAKE_MATCH_<n>\fP variables using
captures from the last match in the file, similar to the
\fI\%string(REGEX MATCHALL)\fP command.  This policy provides
compatibility for projects that have not been updated to expect the behavior.
.sp
The \fBOLD\fP behavior for this policy is for \fI\%file(STRINGS)\fP with
\fBREGEX\fP to not store capture groups in \fI\%CMAKE_MATCH_<n>\fP
variables.  The \fBNEW\fP behavior is to store the capture groups.
.sp
This policy was introduced in CMake version 3.29\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0158
.sp
New in version 3.29.

.sp
\fI\%add_test()\fP honors \fI\%CMAKE_CROSSCOMPILING_EMULATOR\fP only
when \fI\%cross\-compiling\fP\&.
.sp
In CMake 3.28 and below, \fI\%add_test()\fP unconditionally used the
\fI\%CROSSCOMPILING_EMULATOR\fP target property (initialized by the
\fI\%CMAKE_CROSSCOMPILING_EMULATOR\fP variable) to run test commands
naming executable targets.  CMake 3.29 and above prefer to use the emulator
only when the \fI\%CMAKE_CROSSCOMPILING\fP variable is enabled.  The
\fI\%CMAKE_TEST_LAUNCHER\fP variable may be used instead when not
cross\-compiling.  This policy provides compatibility for projects that
have not been updated.
.sp
The \fBOLD\fP behavior for this policy is for \fI\%add_test()\fP to use
the \fI\%CROSSCOMPILING_EMULATOR\fP target property unconditionally.
The \fBNEW\fP behavior for this policy is for \fI\%add_test()\fP to use
the \fI\%CROSSCOMPILING_EMULATOR\fP target property only when
\fI\%cross\-compiling\fP\&.
.sp
This policy was introduced in CMake version 3.29\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0157
.sp
New in version 3.29.

.sp
Swift compilation mode is selected by an abstraction.
.sp
The Swift compiler can compile modules in different modes. The desired build
mode depends whether the developer is iterating and wants to incrementally make
changes, or if they are building a release for distribution and want more
optimizations applied to the resulting binary.
.sp
CMake versions 3.26 through 3.28 build Swift binaries with whole\-module
optimizations enabled when configured in a non\-debug build type.
For CMake versions earlier than 3.26, the developer needs to specify
the necessary flag manually for the \fI\%Ninja Generators\fP, and cannot
not specify whole\-module optimizations to the \fI\%Xcode\fP generator.
.sp
CMake versions 3.29 and above prefer to set the compilation mode using
the \fI\%Swift_COMPILATION_MODE\fP target property, which can be
initialized by the \fI\%CMAKE_Swift_COMPILATION_MODE\fP variable.
.sp
This policy provides compatibility for projects that have not been updated.
The policy setting takes effect as of the first \fI\%project()\fP or
\fI\%enable_language()\fP command that enables the \fBSwift\fP language.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
Once the policy has taken effect at the top of a project, that choice
must be used throughout the tree. In projects that have nested projects
in subdirectories, be sure to convert everything together.
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy builds all Swift targets in
\fBwholemodule\fP mode for non\-debug configurations.  \fI\%Ninja Generators\fP
prepend the \fB\-wmo\fP flag to the default set of Swift flags.
The \fI\%Xcode\fP generator sets the \fBSWIFT_COMPILATION_MODE\fP
attribute to \fBwholemodule\fP in the generated Xcode project file.
.sp
The \fBNEW\fP behavior for this policy is to apply the compilation mode specified
in the \fI\%Swift_COMPILATION_MODE\fP target property, initialized as each
target is created by the \fI\%CMAKE_Swift_COMPILATION_MODE\fP variable.
.sp
This policy was introduced in CMake version 3.29\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0156
.sp
New in version 3.29.

.sp
De\-duplicate libraries on link lines based on linker capabilities.
.sp
Traditional linkers maintain a set of undefined symbols during linking. The
linker processes each file in the order in which it appears on the command
line, until the set of undefined symbols becomes empty. An object file is
linked into the output object when it is encountered, with its undefined
symbols added to the set. Upon encountering an archive file a traditional
linker searches the objects contained therein, and processes those that satisfy
symbols in the unresolved set.
.sp
Handling mutually dependent archives may be awkward when using a traditional
linker. Archive files may have to be specified multiple times.
.sp
Some linkers (for instance Apple or Windows linkers, as well as \fBLLVM LLD\fP)
records all symbols found in objects and archives as it iterates over command
line arguments. When one of these linkers encounters an undefined symbol that
can be resolved by an object file contained in a previously processed archive
file, it immediately extracts and links it into the output object.
.sp
CMake 3.28 and below may generate link lines that repeat static libraries as
a traditional linker would need, even when using a linker does not need it.
They may also de\-duplicate shared libraries by keeping their last occurrence,
which on Windows platforms can change DLL load order.
.sp
CMake 3.29 and above prefer to apply different strategies based on linker
capabilities.  So, when targeting Apple and Windows platforms, all
libraries are de\-duplicated.  Moreover, on Windows platforms, libraries
are de\-duplicated by keeping their fist occurrence, thus respecting the
project\-specified order.  This policy provides compatibility with projects
that have not been updated to expect the latter behavior.
.sp
The \fBOLD\fP behavior for this policy is to always repeat static libraries
as if using a traditional linker, and always de\-duplicate shared libraries
by keeping the last occurrence of each.  The \fBNEW\fP behavior for this policy
is to apply different strategies based on linker capabilities.
.sp
This policy was introduced in CMake version 3.29\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.28
.SS CMP0155
.sp
New in version 3.28.

.sp
C++ sources in targets with at least C++20 are scanned for imports
when supported.
.sp
CMake 3.27 and below assume that C++ sources do not \fBimport\fP modules.
CMake 3.28 and above prefer to assume that C++ sources in targets using C++20
or higher might \fBimport\fP modules, and must be scanned before compiling,
unless explicitly disabled.  This policy provides compatibility for projects
that use C++20 or higher, without modules, that have not been updated to turn
off scanning, e.g., via the \fI\%CMAKE_CXX_SCAN_FOR_MODULES\fP variable.
See the \fI\%cmake\-cxxmodules(7)\fP manual for more details on C++ module
support.
.sp
The \fBOLD\fP behavior for this policy is to assume that C++ 20 and newer
sources do not import modules.  The \fBNEW\fP behavior for this policy is to
assume that C++ 20 and newer files may import modules if the compiler
understands how to scan for their dependencies, and need to be scanned.
.sp
This policy was introduced in CMake version 3.28\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0154
.sp
New in version 3.28.

.sp
Generated files are private by default in targets using \fI\%File Sets\fP\&.
.sp
CMake 3.27 and below assume that any file generated as an output or byproduct
of \fI\%add_custom_command()\fP or \fI\%add_custom_target()\fP may be a
public header file meant for inclusion by dependents\(aq source files.  This
requires \fI\%Ninja Generators\fP to add conservative order\-only dependencies
that prevent a target\(aqs source files from compiling before custom commands
from the target\(aqs dependencies are finished, even if those custom commands
only produce sources private to their own target.
.sp
\fI\%File Sets\fP, introduced by CMake 3.23, provide a way to express the
visibility of generated header files.  CMake 3.28 and above prefer to
assume that, in targets using file sets, generated files are private to
their own target by default.  Generated public headers must be specified
as members of a \fBPUBLIC\fP (or \fBINTERFACE\fP) \fBFILE_SET\fP, typically of
type \fBHEADERS\fP\&.  With this information, \fI\%Ninja Generators\fP may omit
the above\-mentioned conservative dependencies and produce more efficient
build graphs.
.sp
Additionally, if the custom command\(aqs output is a member of a file set of type
\fBCXX_MODULES\fP, it will additionally not be required to exist before
compiling other sources in the same target.  Since these files should not be
included at compile time directly, they may not be implicitly required to
exist for other compilation rules.
.sp
This policy provides compatibility for projects using file sets in targets
with generated header files that have not been updated.  Such projects
should be updated to express generated public headers in a file set.
For example:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
add_custom_command(
  OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/foo.h
  ...
)
target_sources(foo
  PUBLIC FILE_SET HEADERS
    BASE_DIRS ${CMAKE_CURRENT_BINARY_DIR}
    FILES     ${CMAKE_CURRENT_BINARY_DIR}/foo.h
)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to assume generated files are
public, even in targets using file sets, and for \fI\%Ninja Generators\fP
to produce conservative build graphs.  The \fBNEW\fP behavior for this
policy is to assume generated files are private in targets using file sets,
and for \fI\%Ninja Generators\fP to produce more efficient build graphs.
.sp
This policy was introduced in CMake version 3.28\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0153
.sp
New in version 3.28.

.sp
The \fI\%exec_program()\fP command should not be called.
.sp
This command has long been superseded by the \fI\%execute_process()\fP
command and has been deprecated since CMake 3.0.
.sp
CMake >= 3.28 prefer that this command never be called.
The \fBOLD\fP behavior for this policy is to allow the command to be called.
The \fBNEW\fP behavior for this policy is to issue a \fBFATAL_ERROR\fP when the
command is called.
.sp
This policy was introduced in CMake version 3.28\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0152
.sp
New in version 3.28.

.sp
\fI\%file(REAL_PATH)\fP resolves symlinks before collapsing ../ components.
.sp
In CMake 3.27 and below, \fI\%file(REAL_PATH)\fP collapsed any \fB\&../\fP
components in a path before resolving symlinks.  This produced incorrect
results when the \fB\&../\fP collapsed away a symlink.
.sp
The \fBOLD\fP behavior for this policy is to collapse \fB\&../\fP components before
resolving symlinks.
The \fBNEW\fP behavior for this policy is to resolve all symlinks before
collapsing \fB\&../\fP components.
.sp
This policy was introduced in CMake version 3.28\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.27
.SS CMP0151
.sp
New in version 3.27.

.sp
AUTOMOC include directory is a system include directory by default.
.sp
Headers generated for \fI\%AUTOMOC\fP are placed in target\-specific include
directories.  CMake 3.26 and older added these as normal include directories.
CMake 3.27 and newer prefer to add them as system include directories.
This policy provides compatibility for projects that have not been updated
to expect this.
.sp
If the \fI\%AUTOGEN_USE_SYSTEM_INCLUDE\fP target property is set,
perhaps via the \fI\%CMAKE_AUTOGEN_USE_SYSTEM_INCLUDE\fP variable,
then its value is used regardless of the setting of this policy.
.sp
The \fBOLD\fP behavior for this policy is to add autogen include directory to
the target\(aqs include directories.
The \fBNEW\fP behavior for this policy is to add autogen include directory to
the target\(aqs system include directories.
.sp
This policy was introduced in CMake version 3.27\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0150
.sp
New in version 3.27.

.sp
\fI\%ExternalProject_Add()\fP and \fI\%FetchContent_Declare()\fP commands
treat relative \fBGIT_REPOSITORY\fP paths as being relative to the parent
project\(aqs remote.
.sp
Earlier versions of these commands always treated relative paths in
\fBGIT_REPOSITORY\fP as local paths, but the base directory it was treated
as relative to was both undocumented and unintuitive.  The \fBOLD\fP behavior
for this policy is to interpret relative paths used for \fBGIT_REPOSITORY\fP
as local paths relative to the following:
.INDENT 0.0
.IP \(bu 2
The parent directory of \fBSOURCE_DIR\fP for \fI\%ExternalProject_Add()\fP\&.
.IP \(bu 2
\fBFETCHCONTENT_BASE_DIR\fP for \fI\%FetchContent_Declare()\fP\&.
.UNINDENT
.sp
The \fBNEW\fP behavior is to determine the remote from the parent project and
interpret the path relative to that remote.  The value of
\fI\%CMAKE_CURRENT_SOURCE_DIR\fP when \fI\%ExternalProject_Add()\fP or
\fI\%FetchContent_Declare()\fP is called determines the parent project.
The remote is selected according to the following (the first match is used):
.INDENT 0.0
.IP \(bu 2
If the parent project is checked out on a branch with an upstream remote
defined, use that remote.
.IP \(bu 2
If only one remote is defined, use that remote.
.IP \(bu 2
If multiple remotes are defined and one of them is named \fBorigin\fP, use
\fBorigin\fP\(aqs remote but also issue a warning.
.UNINDENT
.sp
If an appropriate remote cannot be determined from the above, a fatal error
will be raised.
.sp
This policy was introduced in CMake version 3.27\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns when a relative path is encountered, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0149
.sp
New in version 3.27.

.sp
\fI\%Visual Studio Generators\fP select latest Windows SDK by default.
.sp
Visual Studio Generators select a Windows SDK version to put in the
\fBWindowsTargetPlatformVersion\fP setting in \fB\&.vcxproj\fP files.
CMake sets the \fI\%CMAKE_VS_WINDOWS_TARGET_PLATFORM_VERSION\fP
variable to the selected SDK version.
.sp
Prior to CMake 3.27, the SDK version was always selected by the value of
the \fI\%CMAKE_SYSTEM_VERSION\fP variable.  Users or toolchain files
could set that variable to one of the exact Windows SDK versions available
on the host system.  Since \fI\%CMAKE_SYSTEM_VERSION\fP defaults to
\fI\%CMAKE_HOST_SYSTEM_VERSION\fP, and it is not guaranteed that a
matching Windows SDK version is available, CMake had to fall back to
using the latest Windows SDK version if no exact match was available.
This approach was problematic:
.INDENT 0.0
.IP \(bu 2
The latest Windows SDK might or might not be selected based on whether
the host version of Windows happens to match an available SDK version.
.IP \(bu 2
An old Windows SDK version might be selected that has not been updated
for newer language standards such as C11.
.UNINDENT
.sp
CMake 3.27 and higher prefer to ignore the exact value of
\fI\%CMAKE_SYSTEM_VERSION\fP and by default select the latest SDK
version available.  An exact SDK version may be specified explicitly
using a \fBversion=\fP field in the \fI\%CMAKE_GENERATOR_PLATFORM\fP
variable.  See \fI\%Visual Studio Platform Selection\fP\&.
.sp
This policy provides compatibility for projects, toolchain files, and
build scripts that have not been ported away from using
\fI\%CMAKE_SYSTEM_VERSION\fP to specify an exact SDK version.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
This policy must be set before the first \fI\%project()\fP or
\fI\%enable_language()\fP command invocation at the top of the
project.  That is when \fI\%Visual Studio Generators\fP select a
Windows SDK.
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to use the exact value of
\fI\%CMAKE_SYSTEM_VERSION\fP if possible.  The \fBNEW\fP behavior
for this policy is to ignore it.
.sp
This policy was introduced in CMake version 3.27\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0148
.sp
New in version 3.27.

.sp
The \fI\%FindPythonInterp\fP and \fI\%FindPythonLibs\fP modules are removed.
.sp
These modules have been deprecated since CMake 3.12.
CMake 3.27 and above prefer to not provide the modules.
This policy provides compatibility for projects that have not been
ported away from them.
.sp
Projects using the \fI\%FindPythonInterp\fP and/or \fI\%FindPythonLibs\fP
modules should be updated to use one of their replacements:
.INDENT 0.0
.IP \(bu 2
\fI\%FindPython3\fP
.IP \(bu 2
\fI\%FindPython2\fP
.IP \(bu 2
\fI\%FindPython\fP
.UNINDENT
.sp
The \fBOLD\fP behavior of this policy is for \fBfind_package(PythonInterp)\fP
and \fBfind_package(PythonLibs)\fP to load the deprecated modules.  The \fBNEW\fP
behavior is for uses of the modules to fail as if they do not exist.
.sp
This policy was introduced in CMake version 3.27\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0147
.sp
New in version 3.27.

.sp
\fI\%Visual Studio Generators\fP build custom commands in parallel.
.sp
Visual Studio 15.8 (2017) and newer support building custom commands in
parallel.  CMake 3.27 and above prefer to enable this behavior by adding
a \fBBuildInParallel\fP setting to custom commands in \fB\&.vcxproj\fP files.
This policy provides compatibility for projects that have not been updated
to expect this, e.g., because their custom commands were accidentally
relying on serial execution by MSBuild.
.sp
The \fBOLD\fP behavior for this policy is to not add \fBBuildInParallel\fP\&.
The \fBNEW\fP behavior for this policy is to add \fBBuildInParallel\fP for
VS 15.8 and newer.
.sp
This policy was introduced in CMake version 3.27\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0146
.sp
New in version 3.27.

.sp
The \fI\%FindCUDA\fP module is removed.
.sp
The \fI\%FindCUDA\fP module has been deprecated since CMake 3.10.
CMake 3.27 and above prefer to not provide the module.
This policy provides compatibility for projects that have not been
ported away from it.
.sp
Projects using the \fI\%FindCUDA\fP module should be updated to use
CMake\(aqs first\-class \fBCUDA\fP language support.  List \fBCUDA\fP among the
languages named in the top\-level call to the \fI\%project()\fP command,
or call the \fI\%enable_language()\fP command with \fBCUDA\fP\&.
Then one can add CUDA (\fB\&.cu\fP) sources directly to targets,
similar to other languages.
.sp
The \fBOLD\fP behavior of this policy is for \fBfind_package(CUDA)\fP to
load the deprecated module.  The \fBNEW\fP behavior is for uses of the
module to fail as if it does not exist.
.sp
This policy was introduced in CMake version 3.27\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0145
.sp
New in version 3.27.

.sp
The \fI\%Dart\fP and \fI\%FindDart\fP modules are removed.
.sp
These modules were added very early in CMake\(aqs development to support
driving tests with a \(dqDART\(dq tool, but DART has not been distributed or
maintained for many years.  Projects would \fBinclude(Dart)\fP to use it,
and the \fBDart\fP module would run \fBfind_package(Dart)\fP internally.
Since \fI\%ctest(1)\fP was created, the \fBDart\fP module has just been
a compatibility shim that finds \fBDart\fP to support some legacy
functionality and then forwards to the \fI\%CTest\fP module.
.sp
CMake 3.27 and above prefer to not provide the \fI\%Dart\fP or
\fI\%FindDart\fP modules.  This policy provides compatibility for
projects that have not been ported away from them.  Projects using the
\fBDart\fP module should be updated to use the \fI\%CTest\fP module directly.
.sp
The \fBOLD\fP behavior of this policy is for \fBinclude(Dart)\fP and
\fBfind_package(Dart)\fP to load the deprecated modules.  The \fBNEW\fP
behavior is for uses of the modules to fail as if they do not exist.
.sp
This policy was introduced in CMake version 3.27\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0144
.sp
New in version 3.27.

.sp
\fI\%find_package()\fP uses upper\-case \fB<PACKAGENAME>_ROOT\fP variables.
.sp
In CMake 3.27 and above the \fI\%find_package(<PackageName>)\fP command now
searches prefixes specified by the upper\-case \fI\%<PACKAGENAME>_ROOT\fP
CMake variable and the \fI\%<PACKAGENAME>_ROOT\fP environment variable
in addition to the case\-preserved \fI\%<PackageName>_ROOT\fP and
\fI\%<PackageName>_ROOT\fP variables used since policy \fI\%CMP0074\fP\&.
This policy provides compatibility with projects that have not been
updated to avoid using \fB<PACKAGENAME>_ROOT\fP variables for other purposes.
.sp
The \fBOLD\fP behavior for this policy is to ignore \fB<PACKAGENAME>_ROOT\fP
variables if the original \fB<PackageName>\fP has lower\-case characters.
The \fBNEW\fP behavior for this policy is to use \fB<PACKAGENAME>_ROOT\fP
variables.
.sp
This policy was introduced in CMake version 3.27\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.26
.SS CMP0143
.sp
New in version 3.26.

.sp
\fI\%USE_FOLDERS\fP global property is treated as \fBON\fP by default.
.sp
When using CMake 3.25 or earlier, \fI\%USE_FOLDERS\fP is treated
as \fBOFF\fP by default unless projects enable the feature.  For example:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_minimum_required(VERSION 3.25)
project(foobar LANGUAGES CXX)
set_property(GLOBAL PROPERTY USE_FOLDERS ON)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
CMake 3.26 and later prefer to enable the feature by default.
.sp
Note that it is the policy setting at the \fIend\fP of the top level
\fBCMakeLists.txt\fP file that matters.  The policy setting applies globally
to the whole project.
.sp
This policy provides compatibility with projects that have not been updated
to expect enabling of folders.  Enabling folders causes projects to appear
differently in IDEs.
.sp
This policy was introduced in CMake version 3.26\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.25
.SS CMP0142
.sp
New in version 3.25.

.sp
The \fI\%Xcode\fP generator does not append per\-config suffixes to
library search paths.
.sp
In CMake 3.24 and below, the \fI\%Xcode\fP generator preceded each
entry of a library search path with a copy of itself appended with
\fB$(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME)\fP\&.  This was left from
very early versions of CMake in which per\-config directories were not well
modeled.  Such paths often do not exist, resulting in warnings from the
toolchain.  CMake 3.25 and above prefer to not add such library search
paths.  This policy provides compatibility for projects that may have been
accidentally relying on the old behavior.
.sp
The \fBOLD\fP behavior for this policy is to append
\fB$(CONFIGURATION)$(EFFECTIVE_PLATFORM_NAME)\fP to all library search paths.
The \fBNEW\fP behavior is to not modify library search paths.
.sp
This policy was introduced in CMake version 3.25\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0141
.sp
New in version 3.25.

.sp
MSVC debug information format flags are selected by an abstraction.
.sp
Compilers targeting the MSVC ABI have flags to select the debug information
format. Debug information format selection typically varies with build
configuration.
.sp
In CMake 3.24 and below, debug information format flags are added to
the default \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP cache entries by CMake
automatically.  This allows users to edit their cache entries to adjust the
flags.  However, the presence of such default flags is problematic for
projects that want to choose a different runtime library programmatically.
In particular, it requires string editing of the
\fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP variables with knowledge of the
CMake builtin defaults so they can be replaced.
.sp
CMake 3.25 and above prefer to leave the debug information format flags
out of the default \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP values and instead
offer a first\-class abstraction.  The
\fI\%CMAKE_MSVC_DEBUG_INFORMATION_FORMAT\fP variable and
\fI\%MSVC_DEBUG_INFORMATION_FORMAT\fP target property may be set to
select the MSVC debug information format.  If they are not set, CMake
enables debug information in debug configurations using the default value
\fB$<$<CONFIG:Debug,RelWithDebInfo>:ProgramDatabase>\fP, if supported by the
compiler, and otherwise \fB$<$<CONFIG:Debug,RelWithDebInfo>:Embedded>\fP\&.
.sp
This policy provides compatibility with projects that have not been updated
to be aware of the abstraction.  The policy setting takes effect as of the
first \fI\%project()\fP or \fI\%enable_language()\fP command that enables
a language whose compiler targets the MSVC ABI.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
Once the policy has taken effect at the top of a project, that choice
will be used throughout the tree.  In projects that have nested projects
in subdirectories, be sure to confirm if everything is working with the
selected policy behavior.
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to place MSVC debug information
format flags in the default \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP cache
entries and ignore the \fI\%CMAKE_MSVC_DEBUG_INFORMATION_FORMAT\fP
abstraction.  The \fBNEW\fP behavior for this policy is to \fInot\fP place MSVC
debug information format flags in the default cache entries and use
the abstraction instead.
.sp
This policy was introduced in CMake version 3.25\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0140
.sp
New in version 3.25.

.sp
The \fI\%return()\fP command checks its parameters.
.sp
The \fBOLD\fP behavior for this policy is to ignore any parameters given to the
command.
The \fBNEW\fP behavior is to check the validity of the parameters.
.sp
This policy was introduced in CMake version 3.25\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.24
.SS CMP0139
.sp
New in version 3.24.

.sp
The \fI\%if()\fP command supports path comparisons using \fBPATH_EQUAL\fP
operator.
.sp
The \fBOLD\fP behavior for this policy is to ignore the \fBPATH_EQUAL\fP operator.
The \fBNEW\fP behavior is to interpret the \fBPATH_EQUAL\fP operator.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0138
.sp
New in version 3.24.

.sp
\fI\%CheckIPOSupported\fP uses flags from calling project.
.sp
The \fI\%CheckIPOSupported\fP module \fI\%check_ipo_supported()\fP
command compiles a test project to determine whether the toolchain
supports \fI\%INTERPROCEDURAL_OPTIMIZATION\fP\&.  CMake 3.23 and
below run the check with the default values of the
\fI\%CMAKE_<LANG>_FLAGS\fP and \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP
variables for the current environment and toolchain settings.
However, some projects may modify these flag variables to add
flags that affect availability of the toolchain\(aqs IPO features.
CMake 3.24 and above prefer to honor the calling project\(aqs values
for these variables.  This policy provides compatibility for projects
that have not been updated to expect this behavior.
.sp
The \fBOLD\fP behavior for this policy is to ignore the calling
project\(aqs values of \fI\%CMAKE_<LANG>_FLAGS\fP and
\fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP\&.  The \fBNEW\fP behavior
for this policy is to use the values of those variables as
compiler flags in the test project.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0137
.sp
New in version 3.24.

.sp
\fI\%try_compile()\fP passes platform variables in project mode.
.sp
The \fI\%try_compile()\fP command \fI\%source file\fP signature propagates CMake variables containing platform settings,
and those specified by the \fI\%CMAKE_TRY_COMPILE_PLATFORM_VARIABLES\fP
variable, into the generated test project.  This helps the test project drive
the toolchain the same way the calling project will.  In CMake 3.23 and below,
the \fI\%whole\-project\fP signature does not
propagate platform variables automatically.  CMake 3.24 and above prefer to
propagate platform variables in the \fI\%whole\-project\fP signature.  This policy provides compatibility with projects that
have not been updated to expect the behavior.
.sp
The \fBOLD\fP behavior for this policy is to not pass any additional variables to
the \fI\%whole\-project\fP signature.
The \fBNEW\fP behavior for this policy is to pass the same variables that the
\fI\%source file\fP signature does.
.sp
Regardless of the policy setting, the
\fI\%CMAKE_TRY_COMPILE_NO_PLATFORM_VARIABLES\fP variable may be set
to suppress passing the platform variables through either signature.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0136
.sp
New in version 3.24.

.sp
Watcom runtime library flags are selected by an abstraction.
.sp
Compilers targeting the Watcom ABI have flags to select the Watcom runtime
library.
.sp
In CMake 3.23 and below, Watcom runtime library selection flags are added to
the default \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP cache entries by CMake
automatically.  This allows users to edit their cache entries to adjust the
flags.  However, the presence of such default flags is problematic for
projects that want to choose a different runtime library programmatically.
In particular, it requires string editing of the
\fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP variables with knowledge of the
CMake builtin defaults so they can be replaced.
.sp
CMake 3.24 and above prefer to leave the Watcom runtime library selection flags
out of the default \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP values and instead
offer a first\-class abstraction.  The \fI\%CMAKE_WATCOM_RUNTIME_LIBRARY\fP
variable and \fI\%WATCOM_RUNTIME_LIBRARY\fP target property may be set to
select the Watcom runtime library.  If they are not set then CMake uses the
default value \fBMultiThreadedDLL\fP on Windows and \fBSingleThreaded\fP on other
platforms, which is equivalent to the original flags.
.sp
This policy provides compatibility with projects that have not been updated
to be aware of the abstraction.  The policy setting takes effect as of the
first \fI\%project()\fP or \fI\%enable_language()\fP command that enables
a language whose compiler targets the Watcom ABI.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
Once the policy has taken effect at the top of a project, that choice
must be used throughout the tree.  In projects that have nested projects
in subdirectories, be sure to convert everything together.
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to place Watcom runtime library
flags in the default \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP cache
entries and ignore the \fI\%CMAKE_WATCOM_RUNTIME_LIBRARY\fP abstraction.
The \fBNEW\fP behavior for this policy is to \fInot\fP place Watcom runtime
library flags in the default cache entries and use the abstraction instead.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0135
.sp
New in version 3.24.

.sp
When using the \fBURL\fP download method with the \fI\%ExternalProject_Add()\fP
command, CMake 3.23 and below sets the timestamps of the extracted contents
to the same as the timestamps in the archive. When the \fBURL\fP changes, the
new archive is downloaded and extracted, but the timestamps of the extracted
contents might not be newer than the previous contents. Anything that depends
on the extracted contents might not be rebuilt, even though the contents may
change.
.sp
CMake 3.24 and above prefers to set the timestamps of all extracted contents
to the time of the extraction. This ensures that anything that depends on the
extracted contents will be rebuilt whenever the \fBURL\fP changes.
.sp
The \fBDOWNLOAD_EXTRACT_TIMESTAMP\fP option to the
\fI\%ExternalProject_Add()\fP command can be used to explicitly specify how
timestamps should be handled. When \fBDOWNLOAD_EXTRACT_TIMESTAMP\fP is not
given, this policy controls the default behavior. The \fBOLD\fP behavior for
this policy is to restore the timestamps from the archive. The \fBNEW\fP
behavior sets the timestamps of extracted contents to the time of extraction.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0134
.sp
New in version 3.24.

.sp
The default registry view is \fBTARGET\fP for the \fI\%find_file()\fP,
\fI\%find_path()\fP, \fI\%find_library()\fP, and \fI\%find_package()\fP
commands and \fBBOTH\fP for the \fI\%find_program()\fP command.
.sp
The default registry views in CMake 3.23 and below are selected using the
following rules:
.INDENT 0.0
.IP \(bu 2
if \fI\%CMAKE_SIZEOF_VOID_P\fP has value \fB8\fP:
.INDENT 2.0
.IP \(bu 2
Use view \fB64\fP for all \fBfind_*\fP commands except \fI\%find_program()\fP
command.
.IP \(bu 2
Use view \fB64_32\fP for \fI\%find_program()\fP command.
.UNINDENT
.IP \(bu 2
if \fI\%CMAKE_SIZEOF_VOID_P\fP has value \fB4\fP or is undefined:
.INDENT 2.0
.IP \(bu 2
Use view \fB32\fP for all \fBfind_*\fP commands except \fI\%find_program()\fP
command.
.IP \(bu 2
Use view \fB32_64\fP for \fI\%find_program()\fP command.
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to use registry views \fB64\fP and
\fB64_32\fP or \fB32_64\fP and \fB32\fP as default, depending of
\fI\%CMAKE_SIZEOF_VOID_P\fP variable value.
The \fBNEW\fP behavior for this policy is to use registry views \fBTARGET\fP and
\fBBOTH\fP as default.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0133
.sp
New in version 3.24.

.sp
The \fI\%CPack\fP module disables SLA by default in the
\fI\%CPack DragNDrop Generator\fP\&.
.sp
The \fI\%CPack DragNDrop Generator\fP in CMake 3.22 and below attach a
Software License Agreement (SLA) to \fB\&.dmg\fP files using the file specified
by \fI\%CPACK_RESOURCE_FILE_LICENSE\fP, if set to a non\-default value.
macOS 12.0 deprecated the tools used to do this, so CMake 3.23 added
the \fI\%CPACK_DMG_SLA_USE_RESOURCE_FILE_LICENSE\fP option to
control the behavior.  CMake 3.23 enables that option by default for
compatibility with older versions. CMake 3.24 and above prefer to \fInot\fP
enable the \fI\%CPACK_DMG_SLA_USE_RESOURCE_FILE_LICENSE\fP option by
default. This policy provides compatibility with projects that have not
been updated to account for the lack of a SLA in their \fB\&.dmg\fP packages.
.sp
The \fBOLD\fP behavior for this policy is to enable
\fI\%CPACK_DMG_SLA_USE_RESOURCE_FILE_LICENSE\fP by default.
The \fBNEW\fP behavior for this policy is to not enable it by default.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0133\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0132
.sp
New in version 3.24.

.sp
Apart from when using the Xcode generator and some Visual Studio generators,
CMake 3.23 and below will set environment variables like \fI\%CC\fP,
\fI\%CXX\fP, etc. when the corresponding language is enabled.
This only occurs on the very first time CMake is run in a build directory,
and the environment variables are only defined at configure time, not build
time. On subsequent CMake runs, these environment variables are not set,
opening up the opportunity for different behavior between the first and
subsequent CMake runs. CMake 3.24 and above prefer to not set these
environment variables when a language is enabled, even on the first run in
a build directory.
.sp
The \fBOLD\fP behavior for this policy sets the relevant environment variable
on the first run when a language is enabled. The \fBNEW\fP behavior for this
policy does not set any such environment variables.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0131
.sp
New in version 3.24.

.sp
\fI\%LINK_LIBRARIES\fP supports the \fI\%$<LINK_ONLY:...>\fP
generator expression.
.sp
CMake 3.23 and below documented the \fI\%$<LINK_ONLY:...>\fP generator
expression only for use in \fI\%INTERFACE_LINK_LIBRARIES\fP\&.
When used in \fI\%LINK_LIBRARIES\fP, the content guarded inside
\fI\%$<LINK_ONLY:...>\fP was always used, even when collecting non\-linking
usage requirements such as \fI\%INTERFACE_COMPILE_DEFINITIONS\fP\&.
.sp
CMake 3.24 and above prefer to support \fI\%$<LINK_ONLY:...>\fP, when
used in \fI\%LINK_LIBRARIES\fP, by using the guarded content only
for link dependencies and not other usage requirements.  This policy
provides compatibility for projects that have not been updated to
account for this change.
.sp
The \fBOLD\fP behavior for this policy is to use \fI\%LINK_LIBRARIES\fP
content guarded by \fI\%$<LINK_ONLY:...>\fP even for non\-linking
usage requirements.  The \fBNEW\fP behavior for this policy is to use
the guarded content only for link dependencies.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0130
.sp
New in version 3.24.

.sp
\fI\%while()\fP diagnoses condition evaluation errors.
.sp
CMake 3.23 and below accidentally tolerated errors encountered while
evaluating the condition passed to the \fI\%while()\fP command
(but not the \fI\%if()\fP command).  For example, the code
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
set(paren \(dq(\(dq)
while(${paren})
endwhile()
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
creates an unbalanced parenthesis during condition evaluation.
.sp
CMake 3.24 and above prefer to diagnose such errors.  This policy
provides compatibility for projects that have not been updated to
fix their condition errors.
.sp
The \fBOLD\fP behavior for this policy is to ignore errors in
\fI\%while()\fP conditions.  The \fBNEW\fP behavior for this
policy is to diagnose errors in \fI\%while()\fP conditions.
.sp
This policy was introduced in CMake version 3.24\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.23
.SS CMP0129
.sp
New in version 3.23.

.sp
Compiler id for MCST LCC compilers is now \fBLCC\fP, not \fBGNU\fP\&.
.sp
CMake 3.23 and above recognize MCST LCC compiler as a different from \fBGNU\fP,
with its own command line and set of capabilities.
CMake now prefers to present this to projects by setting the
\fI\%CMAKE_<LANG>_COMPILER_ID\fP variable to \fBLCC\fP instead
of \fBGNU\fP\&. However, existing projects may assume the compiler id for
LCC is \fBGNU\fP as it was in CMake versions prior to 3.23.
Therefore this policy determines for MCST LCC compiler which
compiler id to report in the \fI\%CMAKE_<LANG>_COMPILER_ID\fP
variable after language \fB<LANG>\fP is enabled by the \fI\%project()\fP
or \fI\%enable_language()\fP command.  The policy must be set prior
to the invocation of either command.
.sp
The \fBOLD\fP behavior for this policy is to use compiler id \fBGNU\fP (and set
\fI\%CMAKE_<LANG>_COMPILER_VERSION\fP to the supported GNU compiler version.)
\fBNEW\fP behavior for this policy is to use compiler id \fBLCC\fP, and set
\fI\%CMAKE_<LANG>_SIMULATE_ID\fP to \fBGNU\fP, and
\fI\%CMAKE_<LANG>_SIMULATE_VERSION\fP to the supported GNU compiler version.
.sp
This policy was introduced in CMake version 3.23\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0129\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.22
.SS CMP0128
.sp
New in version 3.22.

.sp
When this policy is set to \fBNEW\fP:
.INDENT 0.0
.IP \(bu 2
\fI\%<LANG>_EXTENSIONS\fP is initialized to
\fI\%CMAKE_<LANG>_EXTENSIONS\fP if set, otherwise falling back to
\fI\%CMAKE_<LANG>_EXTENSIONS_DEFAULT\fP\&.
.IP \(bu 2
Extensions are correctly enabled/disabled if \fI\%<LANG>_STANDARD\fP is
unset or satisfied by the default.
.IP \(bu 2
Standard mode\-affecting flags aren\(aqt added unless necessary to achieve the
specified mode.
.UNINDENT
.sp
The \fBOLD\fP behavior:
.INDENT 0.0
.IP \(bu 2
Initializes \fI\%<LANG>_EXTENSIONS\fP to
\fI\%CMAKE_<LANG>_EXTENSIONS\fP if set, otherwise falling back to \fBON\fP\&.
.IP \(bu 2
Always adds a flag if \fI\%<LANG>_STANDARD\fP is set and
\fI\%<LANG>_STANDARD_REQUIRED\fP is \fBOFF\fP\&.
.IP \(bu 2
If \fI\%<LANG>_STANDARD\fP is unset:
.INDENT 2.0
.IP \(bu 2
Doesn\(aqt disable extensions even if \fI\%<LANG>_EXTENSIONS\fP is
\fBOFF\fP\&.
.IP \(bu 2
Fails to enable extensions if \fI\%<LANG>_EXTENSIONS\fP is \fBON\fP
except for the \fBIAR\fP compiler.
.UNINDENT
.UNINDENT
.sp
Code may need to be updated for the \fBNEW\fP behavior in the following cases:
.INDENT 0.0
.IP \(bu 2
If a standard mode flag previously overridden by CMake\(aqs and not used during
compiler detection now takes effect due to CMake no longer adding one as the
default detected is appropriate.
.sp
Such code should be converted to either:
.INDENT 2.0
.IP \(bu 2
Use \fI\%<LANG>_STANDARD\fP and \fI\%<LANG>_EXTENSIONS\fP instead
of manually adding flags.
.IP \(bu 2
Or ensure the manually\-specified flags are used during compiler detection.
.UNINDENT
.IP \(bu 2
If extensions were disabled without \fI\%<LANG>_STANDARD\fP being set
CMake previously wouldn\(aqt actually disable extensions.
.sp
Such code should be updated to not disable extensions if they are required.
.IP \(bu 2
If extensions were enabled/disabled when \fI\%<LANG>_STANDARD\fP was
satisfied by the compiler\(aqs default CMake previously wouldn\(aqt actually
enable/disable extensions.
.sp
Such code should be updated to set the correct extensions mode.
.UNINDENT
.sp
If compiler flags affecting the standard mode are used during compiler
detection (for example in \fI\%a toolchain file\fP
using \fI\%CMAKE_<LANG>_FLAGS_INIT\fP) then they will affect the detected
default \fI\%standard\fP and
\fI\%extensions\fP\&.
.sp
This policy was introduced in CMake version 3.22\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0128\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0127
.sp
New in version 3.22.

.sp
\fI\%cmake_dependent_option()\fP supports full \fI\%Condition Syntax\fP\&.
.sp
The \fB<depends>\fP parameter accepts a \fI\%semicolon\-separated list\fP of conditions.  CMake 3.21 and lower evaluates each
\fBcondition\fP as \fBif(${condition})\fP, which does not properly handle
conditions with nested paren groups.  CMake 3.22 and above instead prefer
to evaluate each \fBcondition\fP as \fBif(<condition>)\fP, where \fB<condition>\fP
is re\-parsed as if literally written in a call to \fI\%if()\fP\&.  This
allows expressions like:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
\(dqA AND (B OR C)\(dq
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
but requires expressions like:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
\(dqFOO MATCHES (UPPER|lower)\(dq
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
to be re\-written as:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
\(dqFOO MATCHES \e\(dq(UPPER|lower)\e\(dq\(dq
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Policy \fBCMP0127\fP provides compatibility for projects that have not
been updated to expect the new behavior.
.sp
This policy was introduced in CMake version 3.22\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.21
.SS CMP0126
.sp
New in version 3.21.

.sp
When this policy is set to \fBNEW\fP, the \fI\%set(CACHE)\fP command does not
remove any normal variable of the same name from the current scope.
The \fBOLD\fP behavior removes any normal variable of the same name from the
current scope in the following situations:
.INDENT 0.0
.IP \(bu 2
No cache variable of that name existed previously.
.IP \(bu 2
A cache variable of that name existed previously, but it had no type.
This can occur when the variable was set on the command line using a form
like \fBcmake \-DMYVAR=blah\fP instead of \fBcmake \-DMYVAR:STRING=blah\fP\&.
.IP \(bu 2
The \fBFORCE\fP or \fBINTERNAL\fP keywords were used when setting the cache
variable.
.UNINDENT
.sp
Note that the \fBNEW\fP behavior has an important difference to the similar
\fBNEW\fP behavior of policy \fI\%CMP0077\fP\&.  The \fI\%set(CACHE)\fP
command always sets the cache variable if it did not exist previously,
regardless of the \fBCMP0126\fP policy setting.  The \fI\%option()\fP command
will \fInot\fP set the cache variable if a non\-cache variable of the same name
already exists and \fI\%CMP0077\fP is set to \fBNEW\fP\&.
.sp
This policy was introduced in CMake version 3.21\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0126\fP
variable to control the warning.
.sp
The \fI\%CMAKE_POLICY_DEFAULT_CMP0126\fP
variable may be used to set the policy for a third\-party project in a
subdirectory without modifying it.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0125
.sp
New in version 3.21.

.sp
The \fI\%find_file()\fP, \fI\%find_path()\fP, \fI\%find_library()\fP and
\fI\%find_program()\fP commands cache their result in the variable specified
by their first argument.  Prior to CMake 3.21, if a cache variable of that
name already existed before the call but the cache variable had no type, any
non\-cache variable of the same name would be discarded and the cache variable
was always used (see also \fI\%CMP0126\fP for a different but similar
behavior).  This contradicts the convention that a non\-cache variable should
take precedence over a cache variable of the same name.  Such a situation can
arise if a user sets a cache variable on the command line without specifying
a type, such as \fBcmake \-DMYVAR=blah ...\fP instead of
\fBcmake \-DMYVAR:FILEPATH=blah\fP\&.
.sp
Related to the above, if a cache variable of the specified name already exists
and it \fIdoes\fP have a type, the various \fBfind_...()\fP commands would return
that value unchanged.  In particular, if it contained a relative path, it
would not be converted to an absolute path in this situation.
.sp
When policy \fBCMP0125\fP is set to \fBOLD\fP or is unset, the behavior is as
described above.  When it is set to \fBNEW\fP, the behavior is as follows:
.INDENT 0.0
.IP \(bu 2
If a non\-cache variable of the specified name exists when the \fBfind_...()\fP
command is called, its value will be used regardless of whether a cache
variable of the same name already exists or not.  A cache variable will not
be created in this case if no such cache variable existed before.
If a cache variable of the specified name did already exist, the cache will
be updated to match the non\-cache variable.
.IP \(bu 2
The various \fBfind...()\fP commands will always provide an absolute path in
the result variable, except where a relative path provided by a cache or
non\-cache variable cannot be resolved to an existing path.
.UNINDENT
.sp
This policy was introduced in CMake version 3.21\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0124
.sp
New in version 3.21.

.sp
\fI\%foreach()\fP loop variables are only available in the loop scope.
.sp
CMake 3.20 and below always leave the loop variable set at the end of the
loop, either to the value it had before the loop, if any, or to the empty
string.  CMake 3.21 and above prefer to leave the loop variable in the
state it had before the loop started, either set or unset.  This policy
provides compatibility for projects that expect the loop variable to always
be left set.
.sp
The \fBOLD\fP behavior for this policy is to set the loop variable at the
end of the loop, either to its original value, or to an empty value.
The \fBNEW\fP behavior for this policy is to restore the loop variable to
the state it had before the loop started, either set or unset.
.sp
For example:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
set(items a b c)

set(var1 \(dqvalue\(dq)
unset(var2)

foreach(var1 IN LISTS items)
endforeach()

foreach(var2 IN LISTS items)
endforeach()

if(DEFINED var1)
  message(\(dqvar1: ${var1}\(dq)
endif()
if(DEFINED var2)
  message(\(dqvar2: ${var2}\(dq)
endif()
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Under the \fBOLD\fP behavior, this code prints \fBvar1: value\fP and \fBvar2:\fP\&.
Under the \fBNEW\fP behavior, this code prints only \fBvar1: value\fP\&.
.sp
This policy was introduced in CMake version 3.21\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0123
.sp
New in version 3.21.

.sp
\fBARMClang\fP cpu/arch compile and link flags must be set explicitly.
.sp
CMake 3.20 and lower automatically maps the \fI\%CMAKE_SYSTEM_PROCESSOR\fP
variable and an undocumented \fBCMAKE_SYSTEM_ARCH\fP to compile and link options
for \fBARMClang\fP\&.  For example, the \fB\-mcpu=cortex\-m33\fP flag is added when
\fI\%CMAKE_SYSTEM_PROCESSOR\fP equals \fBcortex\-m33\fP\&.  CMake requires
projects to set either variable or it raises a fatal error.  However, the
project may need to additionally specify CPU features using e.g.
\fB\-mcpu=cortex\-m33+nodsp\fP, conflicting with the \fB\-mcpu=cortex\-m33\fP added
by CMake.  This results in either link errors or unusable binaries.
.sp
CMake 3.21 and above prefer instead to not add any cpu/arch compile and link
flags automatically.  Instead, projects must specify them explicitly.
This policy provides compatibility for projects that have not been updated.
.sp
The \fBOLD\fP behavior of this policy requires projects that use \fBARMClang\fP
to set either \fI\%CMAKE_SYSTEM_PROCESSOR\fP or \fBCMAKE_SYSTEM_ARCH\fP
and it automatically adds a compile option \fB\-mcpu=\fP or \fB\-march=\fP and
a link option \fB\-\-cpu=\fP based on those variables.  The \fBNEW\fP behavior
does not add compile or link options, and projects are responsible for
setting correct options.
.sp
This policy was introduced in CMake version 3.21\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0122
.sp
New in version 3.21.

.sp
\fI\%UseSWIG\fP use library name conventions for \fBCSharp\fP language.
.sp
Starting with CMake 3.21, \fI\%UseSWIG\fP generates now a library using
default naming conventions. This policy provides compatibility with projects
that expect the legacy behavior.
.sp
This policy was introduced in CMake version 3.21\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0121
.sp
New in version 3.21.

.sp
The \fI\%list()\fP command now detects invalid indices.
.sp
Prior to CMake version 3.21, the \fI\%list()\fP command\(aqs \fBGET\fP,
\fBINSERT\fP, \fBSUBLIST\fP, and \fBREMOVE_AT\fP subcommands did not detect invalid
index arguments.
.sp
The \fBOLD\fP behavior of this policy is for invalid indices to be treated as
their integer value (if any) at the start of the string. For example,
\fB2good4you\fP is a \fB2\fP and \fBnot_an_integer\fP is a \fB0\fP\&. The \fBNEW\fP
behavior is for invalid indices to trigger an error.
.sp
This policy was introduced in CMake version 3.21\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.20
.SS CMP0120
.sp
New in version 3.20.

.sp
The \fI\%WriteCompilerDetectionHeader\fP module is removed.
.sp
CMake versions 3.1 through 3.19 provide this module to generate a
C++ compatibility layer by re\-using information from CMake\(aqs table of
preprocessor checks for \fI\%cmake\-compile\-features(7)\fP\&.  However:
.INDENT 0.0
.IP \(bu 2
Those granular features have been superseded by meta\-features for
\fI\%Requiring Language Standards\fP such as \fBcxx_std_11\fP\&.  Therefore
no new granular feature checks will be added and projects will need to
use other means to conditionally use new C++ features.
.IP \(bu 2
The module exposes some of CMake\(aqs implementation details directly
to C++ translation units.
.IP \(bu 2
The module\(aqs approach effectively provides a header file with CMake,
thus tying the version of the header to the version of CMake.
Many projects found that the \fI\%WriteCompilerDetectionHeader\fP was
best used by manually generating its header locally with a recent version
of CMake and then bundling it with the project source so that it could
be used with older CMake versions.
.UNINDENT
.sp
For reasons including the above, CMake 3.20 and above prefer to not
provide the \fI\%WriteCompilerDetectionHeader\fP module.  This policy
provides compatibility for projects that have not been ported away from
it.  Projects using the module should be updated to stop using it.
Alternatives include:
.INDENT 0.0
.IP \(bu 2
Bundle a copy of the generated header in the project\(aqs source.
.IP \(bu 2
Use a third\-party alternative, such as the CC0\-licensed \fI\%Hedley\fP\&.
.IP \(bu 2
Drop support for compilers too old to provide the features natively.
.UNINDENT
.sp
The \fBOLD\fP behavior of this policy is for inclusion of the deprecated
\fI\%WriteCompilerDetectionHeader\fP module to work.  The \fBNEW\fP
behavior is for inclusion of the module to fail as if it does not exist.
.sp
This policy was introduced in CMake version 3.20\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0119
.sp
New in version 3.20.

.sp
\fI\%LANGUAGE\fP source file property explicitly compiles as specified
language.
.sp
The \fI\%LANGUAGE\fP source file property is documented to mean that the
source file is written in the specified language.  In CMake 3.19 and below,
setting this property causes CMake to compile the source file using the
compiler for the specified language.  However, it only passes an explicit
flag to tell the compiler to treat the source as the specified language
for MSVC\-like, XL, and Embarcadero compilers for the \fBCXX\fP language.
CMake 3.20 and above prefer to also explicitly tell the compiler to use
the specified language using a flag such as \fB\-x c\fP on all compilers
for which such flags are known.
.sp
This policy provides compatibility for projects that have not been updated
to expect this behavior.  For example, some projects were setting the
\fBLANGUAGE\fP property to \fBC\fP on assembly\-language \fB\&.S\fP source files
in order to compile them using the C compiler.  Such projects should be
updated to use \fBenable_language(ASM)\fP, for which CMake will often choose
the C compiler as the assembler on relevant platforms anyway.
.sp
The \fBOLD\fP behavior for this policy is to interpret the \fBLANGUAGE <LANG>\fP
property using its undocumented meaning to \(dquse the \fB<LANG>\fP compiler\(dq.
The \fBNEW\fP behavior for this policy is to interpret the \fBLANGUAGE <LANG>\fP
property using its documented meaning to \(dqcompile as a \fB<LANG>\fP source\(dq.
.sp
This policy was introduced in CMake version 3.20\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0118
.sp
New in version 3.20.

.sp
The \fI\%GENERATED\fP source file property is now visible in all directories.
.sp
Whether or not a source file is generated is an all\-or\-nothing global
property of the source.  Consequently, the associated \fBGENERATED\fP
property is now visible from any directory scope, not only from the scope
for which it was set.
.sp
Additionally, the \fBGENERATED\fP property may now be set only to boolean
values, and may not be turned off once turned on.
.sp
The \fBOLD\fP behavior of this policy is to only allow \fBGENERATED\fP to be
visible from the directory scope for which it was set.  The \fBNEW\fP
behavior on the other hand allows it to be visible from any scope.
.sp
This policy was introduced in CMake version 3.20\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn with regard to visibility of the \fBGENERATED\fP
property, but does warn about setting the \fBGENERATED\fP property
to a non\-boolean value,, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0117
.sp
New in version 3.20.

.sp
MSVC RTTI flag \fB/GR\fP is not added to
\fI\%CMAKE_CXX_FLAGS\fP by default.
.sp
When using MSVC\-like compilers in CMake 3.19 and below, the RTTI flag
\fB/GR\fP is added to \fI\%CMAKE_CXX_FLAGS\fP by
default.  This behavior is left from support for MSVC versions from Visual
Studio 2003 and below that did not enable RTTI by default.  It is no longer
necessary.  Furthermore, it is problematic for projects that want to change
to \fB/GR\-\fP programmatically.  In particular, it requires string editing of
the \fI\%CMAKE_CXX_FLAGS\fP variable with knowledge
of the CMake builtin default so it can be replaced.
.sp
CMake 3.20 and above prefer to leave out \fB/GR\fP from the value of
\fI\%CMAKE_CXX_FLAGS\fP by default.
.sp
This policy provides compatibility with projects that have not been updated
to expect the lack of the \fB/GR\fP flag.  The policy setting takes effect as
of the first \fI\%project()\fP or \fI\%enable_language()\fP command that
initializes \fI\%CMAKE_CXX_FLAGS\fP\&.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
Once the policy has taken effect at the top of a project for a given
language, that choice must be used throughout the tree for that language.
In projects that have nested projects in subdirectories, be sure to
convert everything together.
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to place the MSVC \fB/GR\fP flag in the
default \fI\%CMAKE_CXX_FLAGS\fP cache entry.  The
\fBNEW\fP behavior for this policy is to \fInot\fP place the MSVC \fB/GR\fP flag in
the default cache entry.
.sp
This policy was introduced in CMake version 3.20\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0116
.sp
New in version 3.20.

.sp
Ninja generators transform \fBDEPFILE\fP s from \fI\%add_custom_command()\fP\&.
.sp
In CMake 3.19 and below, files given to the \fBDEPFILE\fP argument of
\fI\%add_custom_command()\fP were passed directly to Ninja\(aqs \fBdepfile\fP
variable without any path resolution. This meant that if
\fI\%add_custom_command()\fP was called from a subdirectory (created by
\fI\%add_subdirectory()\fP), the \fBDEPFILE\fP argument would have to be either
an absolute path or a path relative to \fI\%CMAKE_BINARY_DIR\fP, rather
than \fI\%CMAKE_CURRENT_BINARY_DIR\fP\&. In addition, no transformation was
done on the file listed in \fBDEPFILE\fP, which meant that the paths within the
\fBDEPFILE\fP had the same restrictions.
.sp
Starting with CMake 3.20, the \fBDEPFILE\fP argument is relative to
\fI\%CMAKE_CURRENT_BINARY_DIR\fP (unless it is absolute), and the paths in
the \fBDEPFILE\fP are also relative to \fI\%CMAKE_CURRENT_BINARY_DIR\fP\&.
CMake automatically transforms the paths in the \fBDEPFILE\fP (unless they are
absolute) after the custom command is run. The file listed in \fBDEPFILE\fP is
not modified in any way. Instead, CMake writes the transformation to its own
internal file, and passes this internal file to Ninja\(aqs \fBdepfile\fP variable.
This transformation happens regardless of whether or not \fBDEPFILE\fP is
relative, and regardless of whether or not \fI\%add_custom_command()\fP is
called from a subdirectory.
.sp
The \fBOLD\fP behavior for this policy is to pass the \fBDEPFILE\fP to Ninja
unaltered. The \fBNEW\fP behavior for this policy is to transform the \fBDEPFILE\fP
after running the custom command. The status of \fBCMP0116\fP is recorded at the
time of the custom command\(aqs creation, and you can have custom commands in the
same directory with different values for \fBCMP0116\fP by setting the policy
before each custom command.
.sp
This policy was introduced in CMake version 3.20\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default (unless \fBDEPFILE\fP is used in a subdirectory), and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0116\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0115
.sp
New in version 3.20.

.sp
Source file extensions must be explicit.
.sp
In CMake 3.19 and below, if a source file could not be found by the name
specified, it would append a list of known extensions to the name to see if
the file with the extension could be found. For example, this would allow the
user to run:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
add_executable(exe main)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
and put \fBmain.c\fP in the executable without specifying the extension.
.sp
Starting in CMake 3.20, CMake prefers all source files to have their extensions
explicitly listed:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
add_executable(exe main.c)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to implicitly append known extensions
to source files if they can\(aqt be found. The \fBNEW\fP behavior of this policy is
to not append known extensions and require them to be explicit.
.sp
This policy was introduced in CMake version 3.20\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.19
.SS CMP0114
.sp
New in version 3.19.

.sp
\fI\%ExternalProject\fP step targets fully adopt their steps.
.sp
The \fI\%ExternalProject_Add()\fP \fBSTEP_TARGETS\fP option, and the
\fI\%ExternalProject_Add_StepTargets()\fP function, can be used to
create build targets for individual steps of an external project.
.sp
In CMake 3.18 and below, step targets have some limitations:
.INDENT 0.0
.IP \(bu 2
Step targets always depend on targets named by the
\fI\%ExternalProject_Add()\fP \fBDEPENDS\fP option even though
not all steps need them.  In order to allow step targets to be created
without those dependencies, the \fI\%ExternalProject_Add()\fP
\fBINDEPENDENT_STEP_TARGETS\fP option or the
\fI\%ExternalProject_Add_StepTargets()\fP \fBNO_DEPENDS\fP option may
be used.  However, adding such \(dqindependent\(dq step targets makes sense
only for specific steps such as \fBdownload\fP, \fBupdate\fP, and \fBpatch\fP
because they do not need any of the external project\(aqs build dependencies.
Furthermore, it does not make sense to create independent step targets
for steps that depend on non\-independent steps.  Such rules are not
enforced, and projects that do not follow them can generate build systems
with confusing and generator\-specific behavior.
.IP \(bu 2
Step targets hold copies of the custom commands implementing their
steps that are separate from the copies in the primary target created
by \fI\%ExternalProject_Add()\fP, and the primary target does not
depend on the step targets.  In parallel builds that drive the primary
target and step targets concurrently, multiple copies of the steps\(aq
commands may run concurrently and race each other.
.sp
Also, prior to policy \fI\%CMP0113\fP, the step targets generated
by \fI\%Makefile Generators\fP also contain all the custom commands
on which their step depends.  This can lead to repeated execution of
those steps even in serial builds.
.UNINDENT
.sp
In CMake 3.19 and above, the \fI\%ExternalProject\fP module prefers
a revised design to address these problems:
.INDENT 0.0
.IP \(bu 2
Each step is classified as \(dqindependent\(dq if it does not depend
on other targets named by the \fI\%ExternalProject_Add()\fP \fBDEPENDS\fP\&.
The predefined steps are automatically classified by default:
.INDENT 2.0
.IP \(bu 2
The \fBdownload\fP, \fBupdate\fP, and \fBpatch\fP steps are independent.
.IP \(bu 2
The \fBconfigure\fP, \fBbuild\fP, \fBtest\fP, and \fBinstall\fP steps are not.
.UNINDENT
.sp
For custom steps, the \fI\%ExternalProject_Add_Step()\fP command provides
an \fBINDEPENDENT\fP option to mark them as independent.  It is an error to
mark a step as independent if it depends on other steps that are not.  Note
that this use of the term \(dqindependent\(dq refers only to independence from
external targets and is orthogonal to a step\(aqs dependencies on other steps.
.IP \(bu 2
Step targets created by the \fI\%ExternalProject_Add()\fP \fBSTEP_TARGETS\fP
option or the \fI\%ExternalProject_Add_Step()\fP function are now
independent if and only if their steps are marked as independent.
The \fI\%ExternalProject_Add()\fP \fBINDEPENDENT_STEP_TARGETS\fP option
and \fI\%ExternalProject_Add_StepTargets()\fP \fBNO_DEPENDS\fP option
are no longer allowed.
.IP \(bu 2
Step targets, when created, are fully responsible for holding the
custom commands implementing their steps.  The primary target created
by \fI\%ExternalProject_Add()\fP depends on the step targets, and the
step targets depend on each other.  The target\-level dependencies match
the file\-level dependencies used by the custom commands for each step.
.sp
When the \fI\%ExternalProject_Add()\fP \fBUPDATE_DISCONNECTED\fP or
\fBTEST_EXCLUDE_FROM_MAIN\fP option is used, or the
\fI\%ExternalProject_Add_Step()\fP \fBEXCLUDE_FROM_MAIN\fP option is used
for a custom step, some step targets may be created automatically.
These are needed to hold the steps commonly depended upon by the primary
target and the disconnected step targets.
.UNINDENT
.sp
Policy \fBCMP0114\fP provides compatibility for projects that have not been
updated to expect the new behavior.  The \fBOLD\fP behavior for this policy
is to use the above\-documented behavior from 3.18 and below.  The \fBNEW\fP
behavior for this policy is to use the above\-documented behavior preferred
by 3.19 and above.
.sp
This policy was introduced in CMake version 3.19\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0113
.sp
New in version 3.19.

.sp
\fI\%Makefile Generators\fP do not repeat custom commands from target
dependencies.
.sp
Consider a chain of custom commands split across two dependent targets:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
add_custom_command(OUTPUT output\-not\-created
  COMMAND ... DEPENDS ...)
set_property(SOURCE output\-not\-created PROPERTY SYMBOLIC 1)
add_custom_command(OUTPUT output\-created
  COMMAND ... DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/output\-not\-created)
add_custom_target(first DEPENDS output\-not\-created)
add_custom_target(second DEPENDS output\-created)
add_dependencies(second first)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
In CMake 3.18 and lower, the Makefile generators put a copy of both custom
commands in the Makefile for target \fBsecond\fP even though its dependency on
target \fBfirst\fP ensures that the first custom command runs before the second.
Running \fBmake second\fP would cause the first custom command to run once in
the \fBfirst\fP target and then again in the \fBsecond\fP target.
.sp
CMake 3.19 and above prefer to not duplicate custom commands in a target that
are already generated in other targets on which the target depends (directly or
indirectly).  This policy provides compatibility for projects that have not
been updated to expect the new behavior.  In particular, projects that relied
on the duplicate execution or that did not properly set the \fI\%SYMBOLIC\fP
source file property may be affected.
.sp
The \fBOLD\fP behavior for this policy is to duplicate custom commands in
dependent targets.  The \fBNEW\fP behavior of this policy is to not duplicate
custom commands in dependent targets.
.sp
This policy was introduced in CMake version 3.19\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0112
.sp
New in version 3.19.

.sp
Target file component generator expressions do not add target dependencies.
.sp
The following target\-based generator expressions that query for directory or
file name components no longer add a dependency on the evaluated target.
.INDENT 0.0
.INDENT 3.5
.INDENT 0.0
.IP \(bu 2
\fBTARGET_FILE_NAME\fP
.IP \(bu 2
\fBTARGET_FILE_DIR\fP
.IP \(bu 2
\fBTARGET_LINKER_FILE_BASE_NAME\fP
.IP \(bu 2
\fBTARGET_LINKER_FILE_NAME\fP
.IP \(bu 2
\fBTARGET_LINKER_FILE_DIR\fP
.IP \(bu 2
\fBTARGET_SONAME_FILE_NAME\fP
.IP \(bu 2
\fBTARGET_SONAME_FILE_DIR\fP
.IP \(bu 2
\fBTARGET_PDB_FILE_NAME\fP
.IP \(bu 2
\fBTARGET_PDB_FILE_DIR\fP
.IP \(bu 2
\fBTARGET_BUNDLE_DIR\fP
.IP \(bu 2
\fBTARGET_BUNDLE_DIR_NAME\fP
.IP \(bu 2
\fBTARGET_BUNDLE_CONTENT_DIR\fP
.UNINDENT
.UNINDENT
.UNINDENT
.sp
In CMake 3.18 and lower a dependency on the evaluated target of the above
generator expressions would always be added.  CMake 3.19 and above prefer
to not add this dependency.  This policy provides compatibility for projects
that have not been updated to expect the new behavior.  The policy setting
is recorded on each target when it is created, and decides whether generator
expressions referencing that target imply a dependency on it.
.sp
The \fBOLD\fP behavior for this policy is to add a dependency on the evaluated
target for the above generator expressions.  The \fBNEW\fP behavior of
this policy is to not add a dependency on the evaluated target for the
above generator expressions.
.sp
This policy was introduced in CMake version 3.19\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0112\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0111
.sp
New in version 3.19.

.sp
An imported target missing its location property fails during generation.
.sp
\fI\%Imported Targets\fP for library files and executables require that
their location on disk is specified in a target property such as
\fI\%IMPORTED_LOCATION\fP, \fI\%IMPORTED_IMPLIB\fP, or a
per\-configuration equivalent.  If a needed location property is not set,
CMake 3.18 and below generate the string \fB<TARGET_NAME>\-NOTFOUND\fP in
its place, which results in failures of the corresponding rules at build
time.  CMake 3.19 and above prefer instead to raise an error during
generation.  This policy provides compatibility for projects that have
not been updated to expect the new behavior.
.sp
The \fBOLD\fP behavior of this policy is to generate the location of an imported
unknown, static or shared library target as \fB<TARGET_NAME>\-NOTFOUND\fP if not
set.
The \fBNEW\fP behavior is to raise an error.
.sp
This policy was introduced in CMake version 3.19\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0110
.sp
New in version 3.19.

.sp
\fI\%add_test()\fP supports arbitrary characters in test names.
.sp
\fI\%add_test()\fP can now (officially) create tests with whitespace and
other special characters in its name.  Before CMake version 3.19 that was not
allowed, however, it was possible to work around this limitation by explicitly
putting escaped quotes around the test\(aqs name in the \fBadd_test\fP command.
.sp
Although never officially supported several projects in the wild found and
implemented this workaround.  However, the new change which officially allows
the \fBadd_test\fP command to support whitespace and other special characters in
test names now breaks that workaround.  In order for these projects to work
smoothly with newer CMake versions, this policy was introduced.
.sp
The \fBOLD\fP behavior of this policy is to still prevent \fBadd_test\fP from
handling whitespace and special characters properly (if not using the
mentioned workaround).  The \fBNEW\fP behavior on the other hand allows names
with whitespace and special characters for tests created by \fBadd_test\fP\&.
.sp
This policy was introduced in CMake version 3.19\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0109
.sp
New in version 3.19.

.sp
\fI\%find_program()\fP requires permission to execute but not to read.
.sp
In CMake 3.18 and below, the \fI\%find_program()\fP command on UNIX
would find files that are readable without requiring execute permission,
and would not find files that are executable without read permission.
In CMake 3.19 and above, \fBfind_program\fP now prefers to require execute
permission but not read permission.  This policy provides compatibility
with projects that have not been updated to expect the new behavior.
.sp
The \fBOLD\fP behavior for this policy is for \fBfind_program\fP to require
read permission but not execute permission.
The \fBNEW\fP behavior for this policy is for \fBfind_program\fP to require
execute permission but not read permission.
.sp
This policy was introduced in CMake version 3.19\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.18
.SS CMP0108
.sp
New in version 3.18.

.sp
A target is not allowed to link to itself even through an \fBALIAS\fP target.
.sp
In CMake 3.17 and below, a target can link to a target aliased to itself.
.sp
The \fBOLD\fP behavior for this policy is to allow a target to link to a target
aliased to itself.
.sp
The \fBNEW\fP behavior of this policy is to prevent a target to link to itself
through an \fBALIAS\fP target.
.sp
This policy was introduced in CMake version 3.17\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0107
.sp
New in version 3.18.

.sp
It is not allowed to create an \fBALIAS\fP target with the same name as an
another target.
.sp
In CMake 3.17 and below, an \fBALIAS\fP target can overwrite silently an existing
target with the same name.
.sp
The \fBOLD\fP behavior for this policy is to allow target overwrite.
.sp
The \fBNEW\fP behavior of this policy is to prevent target overwriting.
.sp
This policy was introduced in CMake version 3.17\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0106
.sp
New in version 3.18.

.sp
The \fI\%Documentation\fP module is removed.
.sp
The \fI\%Documentation\fP was added as a support mechanism for the VTK
project and was tuned for that project. Instead of CMake providing this module
with (now old) VTK patterns for cache variables and required packages, the
module is now deprecated by CMake itself.
.sp
The \fBOLD\fP behavior of this policy is for \fI\%Documentation\fP to add
cache variables and find VTK documentation dependent packages. The \fBNEW\fP
behavior is to act as an empty module.
.sp
This policy was introduced in CMake version 3.18\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0105
.sp
New in version 3.18.

.sp
\fI\%LINK_OPTIONS\fP and \fI\%INTERFACE_LINK_OPTIONS\fP target
properties are now used for the device link step.
.sp
In CMake 3.17 and below, link options are not used by the device link step.
.sp
The \fBOLD\fP behavior for this policy is to ignore the link options during the
device link step.
.sp
The \fBNEW\fP behavior of this policy is to use the link options during the
device link step.
.sp
This policy was introduced in CMake version 3.18\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0104
.sp
New in version 3.18.

.sp
Initialize \fI\%CMAKE_CUDA_ARCHITECTURES\fP when
\fI\%CMAKE_CUDA_COMPILER_ID\fP is \fBNVIDIA\fP\&.
Raise an error if \fI\%CUDA_ARCHITECTURES\fP is empty.
.sp
\fI\%CMAKE_CUDA_ARCHITECTURES\fP introduced in CMake 3.18 is used to
initialize \fI\%CUDA_ARCHITECTURES\fP, which passes correct code generation
flags to the CUDA compiler.
.sp
Previous to this users had to manually specify the code generation flags. This
policy is for backwards compatibility with manually specifying code generation
flags.
.sp
The \fBOLD\fP behavior for this policy is to not initialize
\fI\%CMAKE_CUDA_ARCHITECTURES\fP when
\fI\%CMAKE_CUDA_COMPILER_ID\fP is \fBNVIDIA\fP\&.
Empty \fI\%CUDA_ARCHITECTURES\fP is allowed.
.sp
The \fBNEW\fP behavior of this policy is to initialize
\fI\%CMAKE_CUDA_ARCHITECTURES\fP when
\fI\%CMAKE_CUDA_COMPILER_ID\fP is \fBNVIDIA\fP
and raise an error if \fI\%CUDA_ARCHITECTURES\fP is empty during generation.
.sp
If \fI\%CUDA_ARCHITECTURES\fP is set to a false value no architectures
flags are passed to the compiler. This is intended to support packagers and
the rare cases where full control over the passed flags is required.
.sp
This policy was introduced in CMake version 3.18\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS Examples
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
set_target_properties(tgt PROPERTIES CUDA_ARCHITECTURES \(dq35;50;72\(dq)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Generates code for real and virtual architectures \fB30\fP, \fB50\fP and \fB72\fP\&.
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
set_property(TARGET tgt PROPERTY CUDA_ARCHITECTURES 70\-real 72\-virtual)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Generates code for real architecture \fB70\fP and virtual architecture \fB72\fP\&.
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
set_property(TARGET tgt PROPERTY CUDA_ARCHITECTURES OFF)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
CMake will not pass any architecture flags to the compiler.
.SS CMP0103
.sp
New in version 3.18.

.sp
Multiple calls to \fI\%export()\fP command with same \fBFILE\fP without
\fBAPPEND\fP is no longer allowed.
.sp
In CMake 3.17 and below, multiple calls to \fI\%export()\fP command with the
same \fBFILE\fP without \fBAPPEND\fP are accepted silently but only the last
occurrence is taken into account during the generation.
.INDENT 0.0
.TP
.B The \fBOLD\fP behavior for this policy is to ignore the multiple occurrences of
\fI\%export()\fP command except the last one.
.UNINDENT
.sp
The \fBNEW\fP behavior of this policy is to raise an error on second call to
\fI\%export()\fP command with same \fBFILE\fP without \fBAPPEND\fP\&.
.sp
This policy was introduced in CMake version 3.18\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.17
.SS CMP0102
.sp
New in version 3.17.

.sp
The \fI\%mark_as_advanced()\fP command no longer creates a cache entry if one
does not already exist.
.sp
In CMake 3.16 and below, if a variable was not defined at all or just defined
locally, the \fI\%mark_as_advanced()\fP command would create a new cache
entry with an \fBUNINITIALIZED\fP type and no value. When a \fI\%find_path()\fP
(or other similar \fBfind_\fP command) would next run, it would find this
undefined cache entry and set it up with an empty string value. This process
would end up deleting the local variable in the process (due to the way the
cache works), effectively clearing any stored \fBfind_\fP results that were only
available in the local scope.
.sp
The \fBOLD\fP behavior for this policy is to create the empty cache definition.
The \fBNEW\fP behavior of this policy is to ignore variables which do not
already exist in the cache.
.sp
This policy was introduced in CMake version 3.17\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the \fI\%CMAKE_POLICY_WARNING_CMP0102\fP variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0101
.sp
New in version 3.17.

.sp
\fI\%target_compile_options()\fP now always honors the \fBBEFORE\fP keyword.
.sp
In CMake 3.16 and below, the \fI\%target_compile_options()\fP command
ignores the \fBBEFORE\fP keyword when inserting items into the
\fI\%COMPILE_OPTIONS\fP target property (\fBPRIVATE\fP and \fBPUBLIC\fP
items).  CMake 3.17 and later honors the \fBBEFORE\fP keyword in all cases.
This policy provides compatibility for projects that have not been updated
to expect the new behavior.
.sp
The behavior of inserting items into the \fI\%INTERFACE_COMPILE_OPTIONS\fP
target property (\fBPUBLIC\fP and \fBINTERFACE\fP items) is not affected by this
policy.  The \fBBEFORE\fP keyword has always been honored when adding items to
\fI\%INTERFACE_COMPILE_OPTIONS\fP\&.
.sp
The \fBOLD\fP behavior for this policy is to not honor the \fBBEFORE\fP keyword
when inserting into the \fI\%COMPILE_OPTIONS\fP property.
The \fBNEW\fP behavior for this policy is to honor the \fBBEFORE\fP keyword in
all cases.
.sp
This policy was introduced in CMake version 3.17\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0100
.sp
New in version 3.17.

.sp
Let \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP process
header files that end with a \fB\&.hh\fP extension.
.sp
Since version 3.17, CMake processes header files that end with a
\fB\&.hh\fP extension in \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP\&.
In earlier CMake versions, these header files were ignored by
\fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP\&.
.sp
This policy affects how header files that end with a \fB\&.hh\fP extension
get treated in \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP\&.
.sp
The \fBOLD\fP behavior for this policy is to ignore \fB\&.hh\fP header files
in \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP\&.
.sp
The \fBNEW\fP behavior for this policy is to process \fB\&.hh\fP header files
in \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP just like other header files.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
To silence the \fBCMP0100\fP warning source files can be excluded from
\fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP processing by setting the
source file properties \fI\%SKIP_AUTOMOC\fP, \fI\%SKIP_AUTOUIC\fP or
\fI\%SKIP_AUTOGEN\fP\&.
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
# Source skip example:
set_property(SOURCE /path/to/file1.hh PROPERTY SKIP_AUTOMOC ON)
set_property(SOURCE /path/to/file2.hh PROPERTY SKIP_AUTOUIC ON)
set_property(SOURCE /path/to/file3.hh PROPERTY SKIP_AUTOGEN ON)
.ft P
.fi
.UNINDENT
.UNINDENT
.UNINDENT
.UNINDENT
.sp
This policy was introduced in CMake version 3.17.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0099
.sp
New in version 3.17.

.sp
Target link properties \fI\%INTERFACE_LINK_OPTIONS\fP,
\fI\%INTERFACE_LINK_DIRECTORIES\fP and \fI\%INTERFACE_LINK_DEPENDS\fP
are now transitive over private dependencies of static libraries.
.sp
In CMake 3.16 and below the interface link properties attached to libraries
are not propagated for private dependencies of static libraries.
Only the libraries themselves are propagated to link the dependent binary.
CMake 3.17 and later prefer to propagate all interface link properties.
This policy provides compatibility for projects that have not been updated
to expect the new behavior.
.sp
The \fBOLD\fP behavior for this policy is to not propagate interface link
properties. The \fBNEW\fP behavior of this policy is to propagate interface link
properties.
.sp
This policy was introduced in CMake version 3.17\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0098
.sp
New in version 3.17.

.sp
\fI\%FindFLEX\fP runs \fBflex\fP in directory
\fI\%CMAKE_CURRENT_BINARY_DIR\fP when executing.
.sp
The module provides a \fBFLEX_TARGET\fP macro which generates FLEX output.
In CMake 3.16 and below the macro would generate a custom command that runs
\fBflex\fP in the current source directory.  CMake 3.17 and later prefer to
run it in the build directory and use \fI\%CMAKE_CURRENT_BINARY_DIR\fP
as the \fBWORKING_DIRECTORY\fP of its \fI\%add_custom_command()\fP invocation.
This ensures that any implicitly generated file is written relative to the
build tree rather than the source tree, unless the generated file is
provided as absolute path.
.sp
This policy provides compatibility for projects that have not been updated
to expect the new behavior.
.sp
The \fBOLD\fP behavior for this policy is for \fBFLEX_TARGET\fP to use
the current source directory for the \fBWORKING_DIRECTORY\fP and where
to generate implicit files. The \fBNEW\fP behavior of this policy is to
use the current binary directory for the \fBWORKING_DIRECTORY\fP relative to
which implicit files are generated unless provided as absolute path.
.sp
This policy was introduced in CMake version 3.17\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.16
.SS CMP0097
.sp
New in version 3.16.

.sp
\fI\%ExternalProject_Add()\fP with \fBGIT_SUBMODULES \(dq\(dq\fP initializes no
submodules.  The policy also applies to \fI\%FetchContent_Declare()\fP,
which uses the same download and update features as
\fI\%ExternalProject_Add()\fP\&.
.sp
The commands provide a \fBGIT_SUBMODULES\fP option which controls what submodules
to initialize and update. Starting with CMake 3.16, explicitly setting
\fBGIT_SUBMODULES\fP to an empty string means no submodules will be initialized
or updated.
.sp
This policy provides compatibility for projects that have not been updated
to expect the new behavior.
.sp
The \fBOLD\fP behavior for this policy is for \fBGIT_SUBMODULES\fP when set to
an empty string to initialize and update all git submodules.
The \fBNEW\fP behavior for this policy is for \fBGIT_SUBMODULES\fP when set to
an empty string to initialize and update no git submodules.
.sp
This policy was introduced in CMake version 3.16\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0096
.sp
New in version 3.16.

.sp
The \fI\%project()\fP command preserves leading zeros in version components.
.sp
When a \fBVERSION <major>[.<minor>[.<patch>[.<tweak>]]]]\fP argument is given
to the \fI\%project()\fP command, it stores the version string in the
\fBPROJECT_VERSION\fP variable and stores individual integer version components
in \fBPROJECT_VERSION_{MAJOR,MINOR,PATCH,TWEAK}\fP variables (see policy
\fI\%CMP0048\fP).  CMake 3.15 and below dropped leading zeros from each
component.  CMake 3.16 and higher prefer to preserve leading zeros.  This
policy provides compatibility for projects that have not been updated to
expect the new behavior.
.sp
The \fBOLD\fP behavior of this policy drops leading zeros in all components,
e.g.  such that version \fB1.07.06\fP becomes \fB1.7.6\fP\&.  The \fBNEW\fP behavior
of this policy preserves the leading zeros in all components, such that
version \fB1.07.06\fP remains unchanged.
.sp
This policy was introduced in CMake version 3.16\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0095
.sp
New in version 3.16.

.sp
\fBRPATH\fP entries are properly escaped in the intermediary CMake install script.
.sp
In CMake 3.15 and earlier, \fBRPATH\fP entries set via
\fI\%CMAKE_INSTALL_RPATH\fP or via \fI\%INSTALL_RPATH\fP have not been
escaped before being inserted into the \fBcmake_install.cmake\fP script. Dynamic
linkers on ELF\-based systems (e.g. Linux and FreeBSD) allow certain keywords in
\fBRPATH\fP entries, such as \fB${ORIGIN}\fP (More details are available in the
\fBld.so\fP man pages on those systems). The syntax of these keywords can match
CMake\(aqs variable syntax. In order to not be substituted (usually to an empty
string) already by the intermediary \fBcmake_install.cmake\fP script, the user had
to double\-escape such \fBRPATH\fP keywords, e.g.
\fBset(CMAKE_INSTALL_RPATH \(dq\e\e\e${ORIGIN}/../lib\(dq)\fP\&. Since the intermediary
\fBcmake_install.cmake\fP script is an implementation detail of CMake, CMake 3.16
and later will make sure \fBRPATH\fP entries are inserted literally by escaping
any coincidental CMake syntax.
.sp
The \fBOLD\fP behavior of this policy is to not escape \fBRPATH\fP entries in the
intermediary \fBcmake_install.cmake\fP script. The \fBNEW\fP behavior is to properly
escape coincidental CMake syntax in \fBRPATH\fP entries when generating the
intermediary \fBcmake_install.cmake\fP script.
.sp
This policy was introduced in CMake version 3.16\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns when it detects use of CMake\-like syntax, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.15
.SS CMP0094
.sp
New in version 3.15.

.sp
Modules \fI\%FindPython3\fP, \fI\%FindPython2\fP and \fI\%FindPython\fP
use \fBLOCATION\fP for lookup strategy.
.sp
Starting with CMake 3.15, Modules \fI\%FindPython3\fP, \fI\%FindPython2\fP
and \fI\%FindPython\fP set value \fBLOCATION\fP for, respectively, variables
\fBPython3_FIND_STRATEGY\fP, \fBPython2_FIND_STRATEGY\fP and
\fBPython_FIND_STRATEGY\fP\&. This policy provides compatibility with projects that
expect the legacy behavior.
.sp
The \fBOLD\fP behavior for this policy set value \fBVERSION\fP for variables
\fBPython3_FIND_STRATEGY\fP, \fBPython2_FIND_STRATEGY\fP and
\fBPython_FIND_STRATEGY\fP\&.
.sp
This policy was introduced in CMake version 3.15\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0093
.sp
New in version 3.15.

.sp
\fI\%FindBoost\fP reports \fBBoost_VERSION\fP in \fBx.y.z\fP format.
.sp
In CMake 3.14 and below the module would report the Boost version
number as specified in the preprocessor definition \fBBOOST_VERSION\fP in
the \fBboost/version.hpp\fP file. In CMake 3.15 and later it is preferred
that the reported version number matches the \fBx.y.z\fP format reported
by the CMake package shipped with Boost \fB1.70.0\fP and later. The macro
value is still reported in the \fBBoost_VERSION_MACRO\fP variable.
.sp
The \fBOLD\fP behavior for this policy is for \fI\%FindBoost\fP to report
\fBBoost_VERSION\fP as specified in the preprocessor definition
\fBBOOST_VERSION\fP in \fBboost/version.hpp\fP\&. The \fBNEW\fP behavior for this
policy is for \fI\%FindBoost\fP to report \fBBoost_VERSION\fP in
\fBx.y.z\fP format.
.sp
This policy was introduced in CMake version 3.15\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0092
.sp
New in version 3.15.

.sp
MSVC warning flags are not in \fI\%CMAKE_<LANG>_FLAGS\fP by default.
.sp
When using MSVC\-like compilers in CMake 3.14 and below, warning flags
like \fB/W3\fP are added to \fI\%CMAKE_<LANG>_FLAGS\fP by default.
This is problematic for projects that want to choose a different warning
level programmatically.  In particular, it requires string editing of the
\fI\%CMAKE_<LANG>_FLAGS\fP variables with knowledge of the
CMake builtin defaults so they can be replaced.
.sp
CMake 3.15 and above prefer to leave out warning flags from the value of
\fI\%CMAKE_<LANG>_FLAGS\fP by default.
.sp
This policy provides compatibility with projects that have not been updated
to expect the lack of warning flags.  The policy setting takes effect as of
the first \fI\%project()\fP or \fI\%enable_language()\fP command that
initializes \fI\%CMAKE_<LANG>_FLAGS\fP for a given language \fB<LANG>\fP\&.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
Once the policy has taken effect at the top of a project for a given
language, that choice must be used throughout the tree for that language.
In projects that have nested projects in subdirectories, be sure to
convert everything together.
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to place MSVC warning flags in the
default \fI\%CMAKE_<LANG>_FLAGS\fP cache entries.  The \fBNEW\fP behavior
for this policy is to \fInot\fP place MSVC warning flags in the default cache
entries.
.sp
This policy was introduced in CMake version 3.15\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0091
.sp
New in version 3.15.

.sp
MSVC runtime library flags are selected by an abstraction.
.sp
Compilers targeting the MSVC ABI have flags to select the MSVC runtime library.
Runtime library selection typically varies with build configuration because
there is a separate runtime library for Debug builds.
.sp
In CMake 3.14 and below, MSVC runtime library selection flags are added to
the default \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP cache entries by CMake
automatically.  This allows users to edit their cache entries to adjust the
flags.  However, the presence of such default flags is problematic for
projects that want to choose a different runtime library programmatically.
In particular, it requires string editing of the
\fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP variables with knowledge of the
CMake builtin defaults so they can be replaced.
.sp
CMake 3.15 and above prefer to leave the MSVC runtime library selection flags
out of the default \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP values and instead
offer a first\-class abstraction.  The \fI\%CMAKE_MSVC_RUNTIME_LIBRARY\fP
variable and \fI\%MSVC_RUNTIME_LIBRARY\fP target property may be set to
select the MSVC runtime library.  If they are not set then CMake uses the
default value \fBMultiThreaded$<$<CONFIG:Debug>:Debug>DLL\fP which is
equivalent to the original flags.
.sp
This policy provides compatibility with projects that have not been updated
to be aware of the abstraction.  The policy setting takes effect as of the
first \fI\%project()\fP or \fI\%enable_language()\fP command that enables
a language whose compiler targets the MSVC ABI.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
Once the policy has taken effect at the top of a project, that choice
must be used throughout the tree.  In projects that have nested projects
in subdirectories, be sure to convert everything together.
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to place MSVC runtime library
flags in the default \fI\%CMAKE_<LANG>_FLAGS_<CONFIG>\fP cache
entries and ignore the \fI\%CMAKE_MSVC_RUNTIME_LIBRARY\fP abstraction.
The \fBNEW\fP behavior for this policy is to \fInot\fP place MSVC runtime
library flags in the default cache entries and use the abstraction instead.
.sp
This policy was introduced in CMake version 3.15\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0090
.sp
New in version 3.15.

.sp
\fI\%export(PACKAGE)\fP does not populate package registry by default.
.sp
In CMake 3.14 and below the \fI\%export(PACKAGE)\fP command populated the
user package registry by default and users needed to set the
\fI\%CMAKE_EXPORT_NO_PACKAGE_REGISTRY\fP to disable it, e.g. in automated
build and packaging environments.  Since the user package registry is stored
outside the build tree, this side effect should not be enabled by default.
Therefore CMake 3.15 and above prefer that \fI\%export(PACKAGE)\fP does
nothing unless an explicit \fI\%CMAKE_EXPORT_PACKAGE_REGISTRY\fP variable
is set to enable it.  This policy provides compatibility with projects that
have not been updated.
.sp
The \fBOLD\fP behavior for this policy is for \fI\%export(PACKAGE)\fP command
to populate the user package registry unless
\fI\%CMAKE_EXPORT_NO_PACKAGE_REGISTRY\fP is enabled.
The \fBNEW\fP behavior is for \fI\%export(PACKAGE)\fP command to do nothing
unless the \fI\%CMAKE_EXPORT_PACKAGE_REGISTRY\fP is enabled.
.sp
This policy was introduced in CMake version 3.15\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0089
.sp
New in version 3.15.

.sp
Compiler id for IBM Clang\-based XL compilers is now \fBXLClang\fP\&.
.sp
CMake 3.15 and above recognize that IBM\(aqs Clang\-based XL compilers
that define \fB__ibmxl__\fP are a new front\-end distinct from \fBxlc\fP
with a different command line and set of capabilities.
CMake now prefers to present this to projects by setting the
\fI\%CMAKE_<LANG>_COMPILER_ID\fP variable to \fBXLClang\fP instead
of \fBXL\fP\&.  However, existing projects may assume the compiler id for
Clang\-based XL is just \fBXL\fP as it was in CMake versions prior to 3.15.
Therefore this policy determines for Clang\-based XL compilers which
compiler id to report in the \fI\%CMAKE_<LANG>_COMPILER_ID\fP
variable after language \fB<LANG>\fP is enabled by the \fI\%project()\fP
or \fI\%enable_language()\fP command.  The policy must be set prior
to the invocation of either command.
.sp
The \fBOLD\fP behavior for this policy is to use compiler id \fBXL\fP\&.  The
\fBNEW\fP behavior for this policy is to use compiler id \fBXLClang\fP\&.
.sp
This policy was introduced in CMake version 3.15\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0089\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.14
.SS CMP0088
.sp
New in version 3.14.

.sp
\fI\%FindBISON\fP runs bison in \fI\%CMAKE_CURRENT_BINARY_DIR\fP
when executing.
.sp
The module provides a \fBBISON_TARGET\fP macro which generates BISON output.
In CMake 3.13 and below the macro would generate a custom command that runs
\fBbison\fP in the source directory.  CMake 3.14 and later prefer to run it
in the build directory and use \fI\%CMAKE_CURRENT_BINARY_DIR\fP as the
\fBWORKING_DIRECTORY\fP of its \fI\%add_custom_command()\fP invocation.
This ensures that any implicitly generated file is written to the build
tree rather than the source.
.sp
This policy provides compatibility for projects that have not been updated
to expect the new behavior.
.sp
The \fBOLD\fP behavior for this policy is for \fBBISON_TARGET\fP to use
the current source directory for the \fBWORKING_DIRECTORY\fP and where
to generate implicit files. The \fBNEW\fP behavior of this policy is to
use the current binary directory for the \fBWORKING_DIRECTORY\fP and where
to generate implicit files.
.sp
This policy was introduced in CMake version 3.14\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0087
.sp
New in version 3.14.

.sp
\fI\%install(CODE)\fP and \fI\%install(SCRIPT)\fP support generator
expressions.
.sp
In CMake 3.13 and earlier, \fI\%install(CODE)\fP and
\fI\%install(SCRIPT)\fP did not evaluate generator expressions.  CMake 3.14
and later will evaluate generator expressions for \fI\%install(CODE)\fP and
\fI\%install(SCRIPT)\fP\&.
.sp
The \fBOLD\fP behavior of this policy is for \fI\%install(CODE)\fP and
\fI\%install(SCRIPT)\fP to not evaluate generator expressions.  The \fBNEW\fP
behavior is to evaluate generator expressions for \fI\%install(CODE)\fP and
\fI\%install(SCRIPT)\fP\&.
.sp
Note that it is the value of this policy setting at the end of the directory
scope that is important, not its setting at the time of the call to
\fI\%install(CODE)\fP or \fI\%install(SCRIPT)\fP\&.  This has implications
for calling these commands from places that have their own policy scope but not
their own directory scope (e.g. from files brought in via \fI\%include()\fP
rather than \fI\%add_subdirectory()\fP).
.sp
This policy was introduced in CMake version 3.14\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0086
.sp
New in version 3.14.

.sp
\fI\%UseSWIG\fP honors \fBSWIG_MODULE_NAME\fP via \fB\-module\fP flag.
.sp
Starting with CMake 3.14, \fI\%UseSWIG\fP passes option
\fB\-module <module_name>\fP to \fBSWIG\fP compiler if the file property
\fBSWIG_MODULE_NAME\fP is specified. This policy provides compatibility with
projects that expect the legacy behavior.
.sp
The \fBOLD\fP behavior for this policy is to never pass \fB\-module\fP option.
The \fBNEW\fP behavior is to pass \fB\-module\fP option to \fBSWIG\fP compiler if
\fBSWIG_MODULE_NAME\fP is specified.
.sp
This policy was introduced in CMake version 3.14\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0085
.sp
New in version 3.14.

.sp
\fB$<IN_LIST:...>\fP handles empty list items.
.sp
In CMake 3.13 and lower, the \fB$<IN_LIST:...>\fP generator expression always
returned \fB0\fP if the first argument was empty, even if the list contained an
empty item. This behavior is inconsistent with the \fBIN_LIST\fP behavior of
\fI\%if()\fP, which this generator expression is meant to emulate. CMake 3.14
and later handles this case correctly.
.sp
The \fBOLD\fP behavior of this policy is for \fB$<IN_LIST:...>\fP to always return
\fB0\fP if the first argument is empty. The \fBNEW\fP behavior is to return \fB1\fP
if the first argument is empty and the list contains an empty item.
.sp
This policy was introduced in CMake version 3.14\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0084
.sp
New in version 3.14.

.sp
The \fI\%FindQt\fP module does not exist for \fI\%find_package()\fP\&.
.sp
The existence of \fI\%FindQt\fP means that for Qt upstream to provide
package config files that can be found by \fBfind_package(Qt)\fP, the consuming
project has to explicitly specify \fBfind_package(Qt CONFIG)\fP\&. Removing this
module gives Qt a path forward for exporting its own config files which can
easily be found by consuming projects.
.sp
This policy pretends that CMake\(aqs internal \fI\%FindQt\fP module does not
exist for \fI\%find_package()\fP\&. If a project really wants to use Qt 3 or 4,
it can call \fBfind_package(Qt[34])\fP, \fBinclude(FindQt)\fP, or add
\fI\%FindQt\fP to their \fI\%CMAKE_MODULE_PATH\fP\&.
.sp
The \fBOLD\fP behavior of this policy is for \fI\%FindQt\fP to exist for
\fI\%find_package()\fP\&. The \fBNEW\fP behavior is to pretend that it doesn\(aqt
exist for \fI\%find_package()\fP\&.
.sp
This policy was introduced in CMake version 3.14\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0083
.sp
New in version 3.14.

.sp
To control generation of Position Independent Executable (\fBPIE\fP) or not, some
flags are required at link time.
.sp
CMake 3.13 and lower did not add these link flags when
\fI\%POSITION_INDEPENDENT_CODE\fP is set.
.sp
The \fBOLD\fP behavior for this policy is to not manage \fBPIE\fP link flags. The
\fBNEW\fP behavior is to add link flags if \fI\%POSITION_INDEPENDENT_CODE\fP
is set:
.INDENT 0.0
.IP \(bu 2
Set to \fBTRUE\fP: flags to produce a position independent executable are
passed to the linker step. For example \fB\-pie\fP for \fBGCC\fP\&.
.IP \(bu 2
Set to \fBFALSE\fP: flags not to produce a position independent executable are
passed to the linker step. For example \fB\-no\-pie\fP for \fBGCC\fP\&.
.IP \(bu 2
Not set: no flags are passed to the linker step.
.UNINDENT
.sp
Since a given linker may not support \fBPIE\fP flags in all environments in
which it is used, it is the project\(aqs responsibility to use the
\fI\%CheckPIESupported\fP module to check for support to ensure that the
\fI\%POSITION_INDEPENDENT_CODE\fP target property for executables will be
honored at link time.
.sp
This policy was introduced in CMake version 3.14\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
Android platform has a special handling of \fBPIE\fP so it is not required
to use the \fI\%CheckPIESupported\fP module to ensure flags are passed to
the linker.
.UNINDENT
.UNINDENT
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS Examples
.sp
Behave like CMake 3.13 and do not apply any \fBPIE\fP flags at link stage.
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_minimum_required(VERSION 3.13)
project(foo)

# ...

add_executable(foo ...)
set_property(TARGET foo PROPERTY POSITION_INDEPENDENT_CODE TRUE)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Use the \fI\%CheckPIESupported\fP module to detect whether \fBPIE\fP is
supported by the current linker and environment.  Apply \fBPIE\fP flags only
if the linker supports them.
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_minimum_required(VERSION 3.14) # CMP0083 NEW
project(foo)

include(CheckPIESupported)
check_pie_supported()

# ...

add_executable(foo ...)
set_property(TARGET foo PROPERTY POSITION_INDEPENDENT_CODE TRUE)
.ft P
.fi
.UNINDENT
.UNINDENT
.SS CMP0082
.sp
New in version 3.14.

.sp
Install rules from \fI\%add_subdirectory()\fP calls are interleaved with
those in caller.
.sp
CMake 3.13 and lower ran the install rules from \fI\%add_subdirectory()\fP
after all other install rules, even if \fI\%add_subdirectory()\fP was called
before the other install rules.  CMake 3.14 and above prefer to interleave
these \fI\%add_subdirectory()\fP install rules with the others so that
they are run in the order they are declared.  This policy provides
compatibility for projects that have not been updated to expect the
new behavior.
.sp
The \fBOLD\fP behavior for this policy is to run the install rules from
\fI\%add_subdirectory()\fP after the other install rules.  The \fBNEW\fP
behavior for this policy is to run all install rules in the order they are
declared.
.sp
This policy was introduced in CMake version 3.14\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0082\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.13
.SS CMP0081
.sp
New in version 3.13.

.sp
Relative paths not allowed in \fI\%LINK_DIRECTORIES\fP target property.
.sp
CMake 3.12 and lower allowed the \fI\%LINK_DIRECTORIES\fP directory
property to contain relative paths.  The base path for such relative
entries is not well defined.  CMake 3.13 and later will issue a
\fBFATAL_ERROR\fP if the \fI\%LINK_DIRECTORIES\fP target property
(which is initialized by the \fI\%LINK_DIRECTORIES\fP directory property)
contains a relative path.
.sp
The \fBOLD\fP behavior for this policy is not to warn about relative paths
in the \fI\%LINK_DIRECTORIES\fP target property.  The \fBNEW\fP behavior for
this policy is to issue a \fBFATAL_ERROR\fP if \fI\%LINK_DIRECTORIES\fP
contains a relative path.
.sp
This policy was introduced in CMake version 3.13\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0080
.sp
New in version 3.13.

.sp
\fI\%BundleUtilities\fP cannot be included at configure time.
.sp
The macros provided by \fI\%BundleUtilities\fP are intended to be invoked
at install time rather than at configure time, because they depend on the
listed targets already existing at the time they are invoked. If they are
invoked at configure time, the targets haven\(aqt been built yet, and the
commands will fail.
.sp
This policy restricts the inclusion of \fI\%BundleUtilities\fP to
\fBcmake \-P\fP style scripts and install rules. Specifically, it looks for the
presence of \fI\%CMAKE_GENERATOR\fP and throws a fatal error if it exists.
.sp
The \fBOLD\fP behavior of this policy is to allow \fI\%BundleUtilities\fP to
be included at configure time. The \fBNEW\fP behavior of this policy is to
disallow such inclusion.
.sp
This policy was introduced in CMake version 3.13\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0079
.sp
New in version 3.13.

.sp
\fI\%target_link_libraries()\fP allows use with targets in other directories.
.sp
Prior to CMake 3.13 the \fI\%target_link_libraries()\fP command did not
accept targets not created in the calling directory as its first argument
for calls that update the \fI\%LINK_LIBRARIES\fP of the target itself.
It did accidentally accept targets from other directories on calls that
only update the \fI\%INTERFACE_LINK_LIBRARIES\fP, but would simply
add entries to the property as if the call were made in the original
directory.  Thus link interface libraries specified this way were always
looked up by generators in the scope of the original target rather than
in the scope that called \fI\%target_link_libraries()\fP\&.
.sp
CMake 3.13 now allows the \fI\%target_link_libraries()\fP command to
be called from any directory to add link dependencies and link interface
libraries to targets created in other directories.  The entries are added
to \fI\%LINK_LIBRARIES\fP and \fI\%INTERFACE_LINK_LIBRARIES\fP
using a special (internal) suffix to tell the generators to look up the
names in the calling scope rather than the scope that created the target.
.sp
This policy provides compatibility with projects that already use
\fI\%target_link_libraries()\fP with the \fBINTERFACE\fP keyword
on a target in another directory to add \fI\%INTERFACE_LINK_LIBRARIES\fP
entries to be looked up in the target\(aqs directory.  Such projects should
be updated to be aware of the new scoping rules in that case.
.sp
The \fBOLD\fP behavior of this policy is to disallow
\fI\%target_link_libraries()\fP calls naming targets from another directory
except in the previously accidentally allowed case of using the \fBINTERFACE\fP
keyword only.  The \fBNEW\fP behavior of this policy is to allow all such
calls but use the new scoping rules.
.sp
This policy was introduced in CMake version 3.13\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0078
.sp
New in version 3.13.

.sp
\fI\%UseSWIG\fP generates standard target names.
.sp
Starting with CMake 3.13, \fI\%UseSWIG\fP generates now standard target
names. This policy provides compatibility with projects that expect the legacy
behavior.
.sp
The \fBOLD\fP behavior for this policy relies on
\fBUseSWIG_TARGET_NAME_PREFERENCE\fP variable that can be used to specify an
explicit preference.  The value may be one of:
.INDENT 0.0
.IP \(bu 2
\fBLEGACY\fP: legacy strategy is applied. Variable
\fBSWIG_MODULE_<name>_REAL_NAME\fP must be used to get real target name.
This is the default if not specified.
.IP \(bu 2
\fBSTANDARD\fP: target name matches specified name.
.UNINDENT
.sp
This policy was introduced in CMake version 3.13\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0077
.sp
New in version 3.13.

.sp
\fI\%option()\fP honors normal variables.
.sp
The \fI\%option()\fP command is typically used to create a cache entry
to allow users to set the option.  However, there are cases in which a
normal (non\-cached) variable of the same name as the option may be
defined by the project prior to calling the \fI\%option()\fP command.
For example, a project that embeds another project as a subdirectory
may want to hard\-code options of the subproject to build the way it needs.
.sp
For historical reasons in CMake 3.12 and below the \fI\%option()\fP
command \fIremoves\fP a normal (non\-cached) variable of the same name when:
.INDENT 0.0
.IP \(bu 2
a cache entry of the specified name does not exist at all, or
.IP \(bu 2
a cache entry of the specified name exists but has not been given
a type (e.g. via \fB\-D<name>=ON\fP on the command line).
.UNINDENT
.sp
In both of these cases (typically on the first run in a new build tree),
the \fI\%option()\fP command gives the cache entry type \fBBOOL\fP and
removes any normal (non\-cached) variable of the same name.  In the
remaining case that the cache entry of the specified name already
exists and has a type (typically on later runs in a build tree), the
\fI\%option()\fP command changes nothing and any normal variable of
the same name remains set.
.sp
In CMake 3.13 and above the \fI\%option()\fP command prefers to
do nothing when a normal variable of the given name already exists.
It does not create or update a cache entry or remove the normal variable.
The new behavior is consistent between the first and later runs in a
build tree.  This policy provides compatibility with projects that have
not been updated to expect the new behavior.
.sp
When the \fI\%option()\fP command sees a normal variable of the given
name:
.INDENT 0.0
.IP \(bu 2
The \fBOLD\fP behavior for this policy is to proceed even when a normal
variable of the same name exists.  If the cache entry does not already
exist and have a type then it is created and/or given a type and the
normal variable is removed.
.IP \(bu 2
The \fBNEW\fP behavior for this policy is to do nothing when a normal
variable of the same name exists.  The normal variable is not removed.
The cache entry is not created or updated and is ignored if it exists.
.UNINDENT
.sp
See \fI\%CMP0126\fP for a similar policy for the \fI\%set(CACHE)\fP
command, but note that there are some differences in \fBNEW\fP behavior
between the two policies.
.sp
This policy was introduced in CMake version 3.13\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
Use the \fI\%CMAKE_POLICY_DEFAULT_CMP0077\fP variable to set the policy for
a third\-party project in a subdirectory without modifying it.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0076
.sp
New in version 3.13.

.sp
The \fI\%target_sources()\fP command converts relative paths to absolute.
.sp
In CMake 3.13 and above, the \fI\%target_sources()\fP command now converts
relative source file paths to absolute paths in the following cases:
.INDENT 0.0
.IP \(bu 2
Source files are added to the target\(aqs \fI\%INTERFACE_SOURCES\fP
property.
.IP \(bu 2
The target\(aqs \fI\%SOURCE_DIR\fP property differs from
\fI\%CMAKE_CURRENT_SOURCE_DIR\fP\&.
.UNINDENT
.sp
A path that begins with a generator expression is always left unmodified.
.sp
This policy provides compatibility with projects that have not been updated
to expect this behavior.  The \fBOLD\fP behavior for this policy is to leave
all relative source file paths unmodified.  The \fBNEW\fP behavior of this
policy is to convert relative paths to absolute according to above rules.
.sp
This policy was introduced in CMake version 3.13\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.12
.SS CMP0075
.sp
New in version 3.12.

.sp
Include file check macros honor \fBCMAKE_REQUIRED_LIBRARIES\fP\&.
.sp
In CMake 3.12 and above, the
.INDENT 0.0
.IP \(bu 2
\fBcheck_include_file\fP macro in the \fI\%CheckIncludeFile\fP module, the
.IP \(bu 2
\fBcheck_include_file_cxx\fP macro in the
\fI\%CheckIncludeFileCXX\fP module, and the
.IP \(bu 2
\fBcheck_include_files\fP macro in the \fI\%CheckIncludeFiles\fP module
.UNINDENT
.sp
now prefer to link the check executable to the libraries listed in the
\fBCMAKE_REQUIRED_LIBRARIES\fP variable.  This policy provides compatibility
with projects that have not been updated to expect this behavior.
.sp
The \fBOLD\fP behavior for this policy is to ignore \fBCMAKE_REQUIRED_LIBRARIES\fP
in the include file check macros.  The \fBNEW\fP behavior of this policy is to
honor \fBCMAKE_REQUIRED_LIBRARIES\fP in the include file check macros.
.sp
This policy was introduced in CMake version 3.12\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0074
.sp
New in version 3.12.

.sp
\fI\%find_package()\fP uses \fB<PackageName>_ROOT\fP variables.
.sp
In CMake 3.12 and above the \fI\%find_package(<PackageName>)\fP command now
searches prefixes specified by the \fI\%<PackageName>_ROOT\fP CMake
variable and the \fI\%<PackageName>_ROOT\fP environment variable.
Package roots are maintained as a stack so nested calls to all \fBfind_*\fP
commands inside find modules and config packages also search the roots as
prefixes.  This policy provides compatibility with projects that have not been
updated to avoid using \fB<PackageName>_ROOT\fP variables for other purposes.
.sp
The \fBOLD\fP behavior for this policy is to ignore \fB<PackageName>_ROOT\fP
variables.  The \fBNEW\fP behavior for this policy is to use
\fB<PackageName>_ROOT\fP variables.
.sp
This policy was introduced in CMake version 3.12\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0073
.sp
New in version 3.12.

.sp
Do not produce legacy \fB_LIB_DEPENDS\fP cache entries.
.sp
Ancient CMake versions once used \fB<tgt>_LIB_DEPENDS\fP cache entries to
propagate library link dependencies.  This has long been done by other
means, leaving the \fI\%export_library_dependencies()\fP command as the
only user of these values.  That command has long been disallowed by
policy \fI\%CMP0033\fP, but the \fB<tgt>_LIB_DEPENDS\fP cache entries
were left for compatibility with possible non\-standard uses by projects.
.sp
CMake 3.12 and above now prefer to not produce these cache entries
at all.  This policy provides compatibility with projects that have
not been updated to avoid using them.
.sp
The \fBOLD\fP behavior for this policy is to set \fB<tgt>_LIB_DEPENDS\fP cache
entries.  The \fBNEW\fP behavior for this policy is to not set them.
.sp
This policy was introduced in CMake version 3.12\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.11
.SS CMP0072
.sp
New in version 3.11.

.sp
\fI\%FindOpenGL\fP prefers GLVND by default when available.
.sp
The \fI\%FindOpenGL\fP module provides an \fBOpenGL::GL\fP target and an
\fBOPENGL_LIBRARIES\fP variable for projects to use for legacy GL interfaces.
When both a legacy GL library (e.g. \fBlibGL.so\fP) and GLVND libraries
for OpenGL and GLX (e.g. \fBlibOpenGL.so\fP and \fBlibGLX.so\fP) are available,
the module must choose between them.  It documents an \fBOpenGL_GL_PREFERENCE\fP
variable that can be used to specify an explicit preference.  When no such
preference is set, the module must choose a default preference.
.sp
CMake 3.11 and above prefer to choose GLVND libraries.  This policy provides
compatibility with projects that expect the legacy GL library to be used.
.sp
The \fBOLD\fP behavior for this policy is to set \fBOpenGL_GL_PREFERENCE\fP to
\fBLEGACY\fP\&.  The \fBNEW\fP behavior for this policy is to set
\fBOpenGL_GL_PREFERENCE\fP to \fBGLVND\fP\&.
.sp
This policy was introduced in CMake version 3.11\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.10
.SS CMP0071
.sp
New in version 3.10.

.sp
Let \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP process
\fI\%GENERATED\fP files.
.sp
Since version 3.10, CMake processes \fBregular\fP and \fI\%GENERATED\fP
source files in \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP\&.
In earlier CMake versions, only \fBregular\fP source files were processed.
\fI\%GENERATED\fP source files were ignored silently.
.sp
This policy affects how source files that are \fI\%GENERATED\fP
get treated in \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP\&.
.sp
The \fBOLD\fP behavior for this policy is to ignore \fI\%GENERATED\fP
source files in \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP\&.
.sp
The \fBNEW\fP behavior for this policy is to process \fI\%GENERATED\fP
source files in \fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP just like regular
source files.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
To silence the \fBCMP0071\fP warning source files can be excluded from
\fI\%AUTOMOC\fP and \fI\%AUTOUIC\fP processing by setting the
source file properties \fI\%SKIP_AUTOMOC\fP, \fI\%SKIP_AUTOUIC\fP or
\fI\%SKIP_AUTOGEN\fP\&.
.UNINDENT
.UNINDENT
.sp
Source skip example:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
# ...
set_property(SOURCE /path/to/file1.h PROPERTY SKIP_AUTOMOC ON)
set_property(SOURCE /path/to/file2.h PROPERTY SKIP_AUTOUIC ON)
set_property(SOURCE /path/to/file3.h PROPERTY SKIP_AUTOGEN ON)
# ...
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
This policy was introduced in CMake version 3.10\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0070
.sp
New in version 3.10.

.sp
Define \fI\%file(GENERATE)\fP behavior for relative paths.
.sp
CMake 3.10 and newer define that relative paths given to \fBINPUT\fP and
\fBOUTPUT\fP arguments of \fBfile(GENERATE)\fP are interpreted relative to the
current source and binary directories, respectively.  CMake 3.9 and lower did
not define any behavior for relative paths but did not diagnose them either
and accidentally treated them relative to the process working directory.
Policy \fBCMP0070\fP provides compatibility with projects that used the old
undefined behavior.
.sp
This policy affects behavior of relative paths given to \fBfile(GENERATE)\fP\&.
The \fBOLD\fP behavior for this policy is to treat the paths relative to the
working directory of CMake.  The \fBNEW\fP behavior for this policy is to
interpret relative paths with respect to the current source or binary
directory of the caller.
.sp
This policy was introduced in CMake version 3.10\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.9
.SS CMP0069
.sp
New in version 3.9.

.sp
\fI\%INTERPROCEDURAL_OPTIMIZATION\fP is enforced when enabled.
.sp
CMake 3.9 and newer prefer to add IPO flags whenever the
\fI\%INTERPROCEDURAL_OPTIMIZATION\fP target property is enabled and
produce an error if flags are not known to CMake for the current compiler.
Since a given compiler may not support IPO flags in all environments in which
it is used, it is now the project\(aqs responsibility to use the
\fI\%CheckIPOSupported\fP module to check for support before enabling the
\fI\%INTERPROCEDURAL_OPTIMIZATION\fP target property.  This approach
allows a project to conditionally activate IPO when supported.  It also
allows an end user to set the \fI\%CMAKE_INTERPROCEDURAL_OPTIMIZATION\fP
variable in an environment known to support IPO even if the project does
not enable the property.
.sp
Since CMake 3.8 and lower only honored \fI\%INTERPROCEDURAL_OPTIMIZATION\fP
for the Intel compiler on Linux, some projects may unconditionally enable the
target property.  Policy \fBCMP0069\fP provides compatibility with such projects.
.sp
This policy takes effect whenever the IPO property is enabled.  The \fBOLD\fP
behavior for this policy is to add IPO flags only for Intel compiler on Linux.
The \fBNEW\fP behavior for this policy is to add IPO flags for the current
compiler or produce an error if CMake does not know the flags.
.sp
This policy was introduced in CMake version 3.9\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS Examples
.sp
Behave like CMake 3.8 and do not apply any IPO flags except for Intel compiler
on Linux:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_minimum_required(VERSION 3.8)
project(foo)

# ...

set_property(TARGET ... PROPERTY INTERPROCEDURAL_OPTIMIZATION TRUE)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Use the \fI\%CheckIPOSupported\fP module to detect whether IPO is
supported by the current compiler, environment, and CMake version.
Produce a fatal error if support is not available:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_minimum_required(VERSION 3.9) # CMP0069 NEW
project(foo)

include(CheckIPOSupported)
check_ipo_supported()

# ...

set_property(TARGET ... PROPERTY INTERPROCEDURAL_OPTIMIZATION TRUE)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Apply IPO flags only if compiler supports it:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_minimum_required(VERSION 3.9) # CMP0069 NEW
project(foo)

include(CheckIPOSupported)

# ...

check_ipo_supported(RESULT result)
if(result)
  set_property(TARGET ... PROPERTY INTERPROCEDURAL_OPTIMIZATION TRUE)
endif()
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Apply IPO flags without any checks.  This may lead to build errors if IPO
is not supported by the compiler in the current environment.  Produce an
error if CMake does not know IPO flags for the current compiler:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_minimum_required(VERSION 3.9) # CMP0069 NEW
project(foo)

# ...

set_property(TARGET ... PROPERTY INTERPROCEDURAL_OPTIMIZATION TRUE)
.ft P
.fi
.UNINDENT
.UNINDENT
.SS CMP0068
.sp
New in version 3.9.

.sp
\fBRPATH\fP settings on macOS do not affect \fBinstall_name\fP\&.
.sp
CMake 3.9 and newer remove any effect the following settings may have on the
\fBinstall_name\fP of a target on macOS:
.INDENT 0.0
.IP \(bu 2
\fI\%BUILD_WITH_INSTALL_RPATH\fP target property
.IP \(bu 2
\fI\%SKIP_BUILD_RPATH\fP target property
.IP \(bu 2
\fI\%CMAKE_SKIP_RPATH\fP variable
.IP \(bu 2
\fI\%CMAKE_SKIP_INSTALL_RPATH\fP variable
.UNINDENT
.sp
Previously, setting \fI\%BUILD_WITH_INSTALL_RPATH\fP had the effect of
setting both the \fBinstall_name\fP of a target to \fI\%INSTALL_NAME_DIR\fP
and the \fBRPATH\fP to \fI\%INSTALL_RPATH\fP\&.  In CMake 3.9, it only affects
setting of \fBRPATH\fP\&.  However, if one wants \fI\%INSTALL_NAME_DIR\fP to
apply to the target in the build tree, one may set
\fI\%BUILD_WITH_INSTALL_NAME_DIR\fP\&.
.sp
If \fI\%SKIP_BUILD_RPATH\fP, \fI\%CMAKE_SKIP_RPATH\fP or
\fI\%CMAKE_SKIP_INSTALL_RPATH\fP were used to strip the directory portion
of the \fBinstall_name\fP of a target, one may set \fBINSTALL_NAME_DIR=\(dq\(dq\fP
instead.
.sp
The \fBOLD\fP behavior of this policy is to use the \fBRPATH\fP settings for
\fBinstall_name\fP on macOS.  The \fBNEW\fP behavior of this policy is to ignore
the \fBRPATH\fP settings for \fBinstall_name\fP on macOS.
.sp
This policy was introduced in CMake version 3.9\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.8
.SS CMP0067
.sp
New in version 3.8.

.sp
Honor language standard in \fI\%try_compile()\fP source\-file signature.
.sp
The \fI\%try_compile()\fP source file signature is intended to allow
callers to check whether they will be able to compile a given source file
with the current toolchain.  In order to match compiler behavior, any
language standard mode should match.  However, CMake 3.7 and below did not
do this.  CMake 3.8 and above prefer to honor the language standard settings
for \fBC\fP, \fBCXX\fP (C++), and \fBCUDA\fP using the values of the variables:
.INDENT 0.0
.IP \(bu 2
\fI\%CMAKE_C_STANDARD\fP
.IP \(bu 2
\fI\%CMAKE_C_STANDARD_REQUIRED\fP
.IP \(bu 2
\fI\%CMAKE_C_EXTENSIONS\fP
.IP \(bu 2
\fI\%CMAKE_CXX_STANDARD\fP
.IP \(bu 2
\fI\%CMAKE_CXX_STANDARD_REQUIRED\fP
.IP \(bu 2
\fI\%CMAKE_CXX_EXTENSIONS\fP
.IP \(bu 2
\fI\%CMAKE_CUDA_STANDARD\fP
.IP \(bu 2
\fI\%CMAKE_CUDA_STANDARD_REQUIRED\fP
.IP \(bu 2
\fI\%CMAKE_CUDA_EXTENSIONS\fP
.UNINDENT
.sp
This policy provides compatibility for projects that do not expect
the language standard settings to be used automatically.
.sp
The \fBOLD\fP behavior of this policy is to ignore language standard
setting variables when generating the \fBtry_compile\fP test project.
The \fBNEW\fP behavior of this policy is to honor language standard
setting variables.
.sp
This policy was introduced in CMake version 3.8\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0067\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.7
.SS CMP0066
.sp
New in version 3.7.

.sp
Honor per\-config flags in \fI\%try_compile()\fP source\-file signature.
.sp
The source file signature of the \fI\%try_compile()\fP command uses the value
of the \fI\%CMAKE_<LANG>_FLAGS\fP variable in the test project so that the
test compilation works as it would in the main project.  However, CMake 3.6 and
below do not also honor config\-specific compiler flags such as those in the
\fI\%CMAKE_<LANG>_FLAGS_DEBUG\fP variable.  CMake 3.7 and above prefer to
honor config\-specific compiler flags too.  This policy provides compatibility
for projects that do not expect config\-specific compiler flags to be used.
.sp
The \fBOLD\fP behavior of this policy is to ignore config\-specific flag
variables like \fI\%CMAKE_<LANG>_FLAGS_DEBUG\fP and only use CMake\(aqs
built\-in defaults for the current compiler and platform.
.sp
The \fBNEW\fP behavior of this policy is to honor config\-specific flag
variabldes like \fI\%CMAKE_<LANG>_FLAGS_DEBUG\fP\&.
.sp
This policy was introduced in CMake version 3.7\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0066\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.4
.SS CMP0065
.sp
New in version 3.4.

.sp
Do not add flags to export symbols from executables without
the \fI\%ENABLE_EXPORTS\fP target property.
.sp
CMake 3.3 and below, for historical reasons, always linked executables
on some platforms with flags like \fB\-rdynamic\fP to export symbols from
the executables for use by any plugins they may load via \fBdlopen\fP\&.
CMake 3.4 and above prefer to do this only for executables that are
explicitly marked with the \fI\%ENABLE_EXPORTS\fP target property.
.sp
The \fBOLD\fP behavior of this policy is to always use the additional link
flags when linking executables regardless of the value of the
\fI\%ENABLE_EXPORTS\fP target property.
.sp
The \fBNEW\fP behavior of this policy is to only use the additional link
flags when linking executables if the \fI\%ENABLE_EXPORTS\fP target
property is set to \fBTrue\fP\&.
.sp
This policy was introduced in CMake version 3.4\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0065\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0064
.sp
New in version 3.4.

.sp
Recognize \fBTEST\fP as a operator for the \fI\%if()\fP command.
.sp
The \fBTEST\fP operator was added to the \fI\%if()\fP command to determine if a
given test name was created by the \fI\%add_test()\fP command.
.sp
The \fBOLD\fP behavior for this policy is to ignore the \fBTEST\fP operator.
The \fBNEW\fP behavior is to interpret the \fBTEST\fP operator.
.sp
This policy was introduced in CMake version 3.4\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.3
.SS CMP0063
.sp
New in version 3.3.

.sp
Honor visibility properties for all target types.
.sp
The \fI\%<LANG>_VISIBILITY_PRESET\fP and
\fI\%VISIBILITY_INLINES_HIDDEN\fP target properties affect visibility
of symbols during dynamic linking.  When first introduced these properties
affected compilation of sources only in shared libraries, module libraries,
and executables with the \fI\%ENABLE_EXPORTS\fP property set.  This
was sufficient for the basic use cases of shared libraries and executables
with plugins.  However, some sources may be compiled as part of static
libraries or object libraries and then linked into a shared library later.
CMake 3.3 and above prefer to honor these properties for sources compiled
in all target types.  This policy preserves compatibility for projects
expecting the properties to work only for some target types.
.sp
The \fBOLD\fP behavior for this policy is to ignore the visibility properties
for static libraries, object libraries, and executables without exports.
The \fBNEW\fP behavior for this policy is to honor the visibility properties
for all target types.
.sp
This policy was introduced in CMake version 3.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0062
.sp
New in version 3.3.

.sp
Disallow \fI\%install()\fP of \fI\%export()\fP result.
.sp
The \fI\%export()\fP command generates a file containing
\fI\%Imported Targets\fP, which is suitable for use from the build
directory.  It is not suitable for installation because it contains absolute
paths to buildsystem locations, and is particular to a single build
configuration.
.sp
The \fI\%install(EXPORT)\fP generates and installs files which contain
\fI\%Imported Targets\fP\&.  These files are generated with relative paths
(unless the user specifies absolute paths), and are designed for
multi\-configuration use.  See \fI\%Creating Packages\fP for more.
.sp
CMake 3.3 no longer allows the use of the \fI\%install(FILES)\fP command
with the result of the \fI\%export()\fP command.
.sp
The \fBOLD\fP behavior for this policy is to allow installing the result of
an \fI\%export()\fP command.  The \fBNEW\fP behavior for this policy is
not to allow installing the result of an \fI\%export()\fP command.
.sp
This policy was introduced in CMake version 3.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0061
.sp
New in version 3.3.

.sp
CTest does not by default tell \fBmake\fP to ignore errors (\fB\-i\fP).
.sp
The \fI\%ctest_build()\fP and \fI\%build_command()\fP commands no
longer generate build commands for \fI\%Makefile Generators\fP with
the \fB\-i\fP option.  Previously this was done to help build as much
of tested projects as possible.  However, this behavior is not
consistent with other generators and also causes the return code
of the \fBmake\fP tool to be meaningless.
.sp
Of course users may still add this option manually by setting
\fI\%CTEST_BUILD_COMMAND\fP or the \fBMAKECOMMAND\fP cache entry.
See the \fI\%CTest Build Step\fP \fBMakeCommand\fP setting documentation
for their effects.
.sp
The \fBOLD\fP behavior for this policy is to add \fB\-i\fP to \fBmake\fP
calls in CTest.  The \fBNEW\fP behavior for this policy is to not
add \fB\-i\fP\&.
.sp
This policy was introduced in CMake version 3.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0060
.sp
New in version 3.3.

.sp
Link libraries by full path even in implicit directories.
.sp
Policy \fI\%CMP0003\fP was introduced with the intention of always
linking library files by full path when a full path is given to the
\fI\%target_link_libraries()\fP command.  However, on some platforms
(e.g. HP\-UX) the compiler front\-end adds alternative library search paths
for the current architecture (e.g. \fB/usr/lib/<arch>\fP has alternatives
to libraries in \fB/usr/lib\fP for the current architecture).
On such platforms the \fI\%find_library()\fP may find a library such as
\fB/usr/lib/libfoo.so\fP that does not belong to the current architecture.
.sp
Prior to policy \fI\%CMP0003\fP projects would still build in such
cases because the incorrect library path would be converted to \fB\-lfoo\fP
on the link line and the linker would find the proper library in the
arch\-specific search path provided by the compiler front\-end implicitly.
At the time we chose to remain compatible with such projects by always
converting library files found in implicit link directories to \fB\-lfoo\fP
flags to ask the linker to search for them.  This approach allowed existing
projects to continue to build while still linking to libraries outside
implicit link directories via full path (such as those in the build tree).
.sp
CMake does allow projects to override this behavior by using an
\fI\%IMPORTED library target\fP with its
\fI\%IMPORTED_LOCATION\fP property set to the desired full path to
a library file.  In fact, many \fI\%Find Modules\fP are learning to provide
\fI\%Imported Targets\fP instead of just the traditional \fBFoo_LIBRARIES\fP
variable listing library files.  However, this makes the link line
generated for a library found by a Find Module depend on whether it
is linked through an imported target or not, which is inconsistent.
Furthermore, this behavior has been a source of confusion because the
generated link line for a library file depends on its location.  It is
also problematic for projects trying to link statically because flags
like \fB\-Wl,\-Bstatic \-lfoo \-Wl,\-Bdynamic\fP may be used to help the linker
select \fBlibfoo.a\fP instead of \fBlibfoo.so\fP but then leak dynamic linking
to following libraries.  (See the \fI\%LINK_SEARCH_END_STATIC\fP
target property for a solution typically used for that problem.)
.sp
When the special case for libraries in implicit link directories was first
introduced the list of implicit link directories was simply hard\-coded
(e.g. \fB/lib\fP, \fB/usr/lib\fP, and a few others).  Since that time, CMake
has learned to detect the implicit link directories used by the compiler
front\-end.  If necessary, the \fI\%find_library()\fP command could be
taught to use this information to help find libraries of the proper
architecture.
.sp
For these reasons, CMake 3.3 and above prefer to drop the special case
and link libraries by full path even when they are in implicit link
directories.  Policy \fBCMP0060\fP provides compatibility for existing
projects.
.sp
The \fBOLD\fP behavior for this policy is to ask the linker to search for
libraries whose full paths are known to be in implicit link directories.
The \fBNEW\fP behavior for this policy is to link libraries by full path even
if they are in implicit link directories.
.sp
This policy was introduced in CMake version 3.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0060\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0059
.sp
New in version 3.3.

.sp
Do not treat \fBDEFINITIONS\fP as a built\-in directory property.
.sp
CMake 3.3 and above no longer make a list of definitions available through
the \fI\%DEFINITIONS\fP directory property.  The
\fI\%COMPILE_DEFINITIONS\fP directory property may be used instead.
.sp
The \fBOLD\fP behavior for this policy is to provide the list of flags given
so far to the \fI\%add_definitions()\fP command.  The \fBNEW\fP behavior is
to behave as a normal user\-defined directory property.
.sp
This policy was introduced in CMake version 3.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0058
.sp
New in version 3.3.

.sp
Ninja requires custom command byproducts to be explicit.
.sp
When an intermediate file generated during the build is consumed
by an expensive operation or a large tree of dependents, one may
reduce the work needed for an incremental rebuild by updating the
file timestamp only when its content changes.  With this approach
the generation rule must have a separate output file that is always
updated with a new timestamp that is newer than any dependencies of
the rule so that the build tool re\-runs the rule only when the input
changes.  We refer to the separate output file as a rule\(aqs \fIwitness\fP
and the generated file as a rule\(aqs \fIbyproduct\fP\&.
.sp
Byproducts may not be listed as outputs because their timestamps are
allowed to be older than the inputs.  No build tools (like \fBmake\fP)
that existed when CMake was designed have a way to express byproducts.
Therefore CMake versions prior to 3.2 had no way to specify them.
Projects typically left byproducts undeclared in the rules that
generate them.  For example:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
add_custom_command(
  OUTPUT witness.txt
  COMMAND ${CMAKE_COMMAND} \-E copy_if_different
          ${CMAKE_CURRENT_SOURCE_DIR}/input.txt
          byproduct.txt # timestamp may not change
  COMMAND ${CMAKE_COMMAND} \-E touch witness.txt
  DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/input.txt
  )
add_custom_target(Provider DEPENDS witness.txt)
add_custom_command(
  OUTPUT generated.c
  COMMAND expensive\-task \-i byproduct.txt \-o generated.c
  DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/byproduct.txt
  )
add_library(Consumer generated.c)
add_dependencies(Consumer Provider)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
This works well for all generators except \fI\%Ninja\fP\&.
The Ninja build tool sees a rule listing \fBbyproduct.txt\fP
as a dependency and no rule listing it as an output.  Ninja then
complains that there is no way to satisfy the dependency and
stops building even though there are order\-only dependencies
that ensure \fBbyproduct.txt\fP will exist before its consumers
need it.  See discussion of this problem in \fI\%Ninja Issue 760\fP
for further details on why Ninja works this way.
.sp
Instead of leaving byproducts undeclared in the rules that generate
them, Ninja expects byproducts to be listed along with other outputs.
Such rules may be marked with a \fBrestat\fP option that tells Ninja
to check the timestamps of outputs after the rules run.  This
prevents byproducts whose timestamps do not change from causing
their dependents to re\-build unnecessarily.
.sp
Since the above approach does not tell CMake what custom command
generates \fBbyproduct.txt\fP, the Ninja generator does not have
enough information to add the byproduct as an output of any rule.
CMake 2.8.12 and above work around this problem and allow projects
using the above approach to build by generating \fBphony\fP build
rules to tell Ninja to tolerate such missing files.  However, this
workaround prevents Ninja from diagnosing a dependency that is
really missing.  It also works poorly in in\-source builds where
every custom command dependency, even on source files, needs to
be treated this way because CMake does not have enough information
to know which files are generated as byproducts of custom commands.
.SS Introducing Byproducts
.sp
CMake 3.2 introduced the \fBBYPRODUCTS\fP option to the
\fI\%add_custom_command()\fP and \fI\%add_custom_target()\fP
commands.  This option allows byproducts to be specified explicitly:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
add_custom_command(
  OUTPUT witness.txt
  BYPRODUCTS byproduct.txt # explicit byproduct specification
  COMMAND ${CMAKE_COMMAND} \-E copy_if_different
          ${CMAKE_CURRENT_SOURCE_DIR}/input.txt
          byproduct.txt # timestamp may not change
\&...
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
The \fBBYPRODUCTS\fP option is used by the \fI\%Ninja\fP generator
to list byproducts among the outputs of the custom commands that
generate them, and is ignored by other generators.
.sp
CMake 3.3 and above prefer to require projects to specify custom
command byproducts explicitly so that it can avoid using the
\fBphony\fP rule workaround altogether.  Policy \fBCMP0058\fP was
introduced to provide compatibility with existing projects that
still need the workaround.
.sp
This policy has no effect on generators other than \fI\%Ninja\fP\&.
The \fBOLD\fP behavior for this policy is to generate Ninja \fBphony\fP
rules for unknown dependencies in the build tree.  The \fBNEW\fP
behavior for this policy is to not generate these and instead
require projects to specify custom command \fBBYPRODUCTS\fP explicitly.
.sp
This policy was introduced in CMake version 3.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns when it sees unknown dependencies in out\-of\-source build trees, and uses \fBOLD\fP behavior.
.sp
The policy setting must be in scope at the end of the top\-level
\fBCMakeLists.txt\fP file of the project and has global effect.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0057
.sp
New in version 3.3.

.sp
Support new \fI\%if()\fP IN_LIST operator.
.sp
CMake 3.3 adds support for the new IN_LIST operator.
.sp
The \fBOLD\fP behavior for this policy is to ignore the IN_LIST operator.
The \fBNEW\fP behavior is to interpret the IN_LIST operator.
.sp
This policy was introduced in CMake version 3.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.2
.SS CMP0056
.sp
New in version 3.2.

.sp
Honor link flags in \fI\%try_compile()\fP source\-file signature.
.sp
The \fI\%try_compile()\fP command source\-file signature generates a
\fBCMakeLists.txt\fP file to build the source file into an executable.
In order to compile the source the same way as it might be compiled
by the calling project, the generated project sets the value of the
\fI\%CMAKE_<LANG>_FLAGS\fP variable to that in the calling project.
The value of the \fI\%CMAKE_EXE_LINKER_FLAGS\fP variable may be
needed in some cases too, but CMake 3.1 and lower did not set it in
the generated project.  CMake 3.2 and above prefer to set it so that
linker flags are honored as well as compiler flags.  This policy
provides compatibility with the pre\-3.2 behavior.
.sp
The \fBOLD\fP behavior for this policy is to not set the value of the
\fI\%CMAKE_EXE_LINKER_FLAGS\fP variable in the generated test
project.  The \fBNEW\fP behavior for this policy is to set the value of
the \fI\%CMAKE_EXE_LINKER_FLAGS\fP variable in the test project
to the same as it is in the calling project.
.sp
If the project code does not set the policy explicitly, users may
set it on the command line by defining the
\fI\%CMAKE_POLICY_DEFAULT_CMP0056\fP
variable in the cache.
.sp
This policy was introduced in CMake version 3.2\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0056\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0055
.sp
New in version 3.2.

.sp
Strict checking for the \fI\%break()\fP command.
.sp
CMake 3.1 and lower allowed calls to the \fI\%break()\fP command
outside of a loop context and also ignored any given arguments.
This was undefined behavior.
.sp
The \fBOLD\fP behavior for this policy is to allow \fI\%break()\fP to be placed
outside of loop contexts and ignores any arguments.  The \fBNEW\fP behavior for this
policy is to issue an error if a misplaced break or any arguments are found.
.sp
This policy was introduced in CMake version 3.2\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.1
.SS CMP0054
.sp
New in version 3.1.

.sp
Only interpret \fI\%if()\fP arguments as variables or keywords when unquoted.
.sp
CMake 3.1 and above no longer implicitly dereference variables or
interpret keywords in an \fI\%if()\fP command argument when
it is a \fI\%Quoted Argument\fP or a \fI\%Bracket Argument\fP\&.
.sp
The \fBOLD\fP behavior for this policy is to dereference variables and
interpret keywords even if they are quoted or bracketed.
The \fBNEW\fP behavior is to not dereference variables or interpret keywords
that have been quoted or bracketed.
.sp
Given the following partial example:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
set(A E)
set(E \(dq\(dq)

if(\(dq${A}\(dq STREQUAL \(dq\(dq)
  message(\(dqResult is TRUE before CMake 3.1 or when CMP0054 is OLD\(dq)
else()
  message(\(dqResult is FALSE in CMake 3.1 and above if CMP0054 is NEW\(dq)
endif()
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
After explicit expansion of variables this gives:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
if(\(dqE\(dq STREQUAL \(dq\(dq)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
With the policy set to \fBOLD\fP implicit expansion reduces this semantically to:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
if(\(dq\(dq STREQUAL \(dq\(dq)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
With the policy set to \fBNEW\fP the quoted arguments will not be
further dereferenced:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
if(\(dqE\(dq STREQUAL \(dq\(dq)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
This policy was introduced in CMake version 3.1\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0053
.sp
New in version 3.1.

.sp
Simplify variable reference and escape sequence evaluation.
.sp
CMake 3.1 introduced a much faster implementation of evaluation of the
\fI\%Variable References\fP and \fI\%Escape Sequences\fP documented in the
\fI\%cmake\-language(7)\fP manual.  While the behavior is identical
to the legacy implementation in most cases, some corner cases were
cleaned up to simplify the behavior.  Specifically:
.INDENT 0.0
.IP \(bu 2
Expansion of \fB@VAR@\fP reference syntax defined by the
\fI\%configure_file()\fP and \fI\%string(CONFIGURE)\fP
commands is no longer performed in other contexts.
.IP \(bu 2
Literal \fB${VAR}\fP reference syntax may contain only
alphanumeric characters (\fBA\-Z\fP, \fBa\-z\fP, \fB0\-9\fP) and
the characters \fB_\fP, \fB\&.\fP, \fB/\fP, \fB\-\fP, and \fB+\fP\&.
Note that \fB$\fP is technically allowed in the \fBNEW\fP behavior, but is
invalid for \fBOLD\fP behavior.  This is due to an oversight during the
implementation of \fBCMP0053\fP and its use as a literal variable
reference is discouraged for this reason.
Variables with other characters in their name may still
be referenced indirectly, e.g.
.INDENT 2.0
.INDENT 3.5
.sp
.nf
.ft C
set(varname \(dqotherwise & disallowed $ characters\(dq)
message(\(dq${${varname}}\(dq)
.ft P
.fi
.UNINDENT
.UNINDENT
.IP \(bu 2
The setting of policy \fI\%CMP0010\fP is not considered,
so improper variable reference syntax is always an error.
.IP \(bu 2
More characters are allowed to be escaped in variable names.
Previously, only \fB()#\(dq \e@^\fP were valid characters to
escape. Now any non\-alphanumeric, non\-semicolon, non\-NUL
character may be escaped following the \fBescape_identity\fP
production in the \fI\%Escape Sequences\fP section of the
\fI\%cmake\-language(7)\fP manual.
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to honor the legacy behavior for
variable references and escape sequences.  The \fBNEW\fP behavior is to
use the simpler variable expansion and escape sequence evaluation rules.
.sp
This policy was introduced in CMake version 3.1\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0052
.sp
New in version 3.1.

.sp
Reject source and build dirs in installed
\fI\%INTERFACE_INCLUDE_DIRECTORIES\fP\&.
.sp
CMake 3.0 and lower allowed subdirectories of the source directory or build
directory to be in the \fI\%INTERFACE_INCLUDE_DIRECTORIES\fP of
installed and exported targets, if the directory was also a subdirectory of
the installation prefix.  This makes the installation depend on the
existence of the source dir or binary dir, and the installation will be
broken if either are removed after installation.
.sp
See \fI\%Include Directories and Usage Requirements\fP for more on
specifying include directories for targets.
.sp
The \fBOLD\fP behavior for this policy is to export the content of the
\fI\%INTERFACE_INCLUDE_DIRECTORIES\fP with the source or binary
directory.  The \fBNEW\fP behavior for this
policy is to issue an error if such a directory is used.
.sp
This policy was introduced in CMake version 3.1\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0051
.sp
New in version 3.1.

.sp
List \fI\%TARGET_OBJECTS\fP in SOURCES target property.
.sp
CMake 3.0 and lower did not include the \fBTARGET_OBJECTS\fP
\fI\%generator expression\fP when
returning the \fI\%SOURCES\fP target property.
.sp
Configure\-time CMake code is not able to handle generator expressions.  If
using the \fI\%SOURCES\fP target property at configure time, it may be
necessary to first remove generator expressions using the
\fI\%string(GENEX_STRIP)\fP command.  Generate\-time CMake code such as
\fI\%file(GENERATE)\fP can handle the content without stripping.
.sp
The \fBOLD\fP behavior for this policy is to omit \fBTARGET_OBJECTS\fP
expressions from the \fI\%SOURCES\fP target property.  The \fBNEW\fP
behavior for this policy is to include \fBTARGET_OBJECTS\fP expressions
in the output.
.sp
This policy was introduced in CMake version 3.1\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 3.0
.SS CMP0050
.sp
Disallow add_custom_command SOURCE signatures.
.sp
CMake 2.8.12 and lower allowed a signature for \fI\%add_custom_command()\fP
which specified an input to a command.  This was undocumented behavior.
Modern use of CMake associates custom commands with their output, rather
than their input.
.sp
The \fBOLD\fP behavior for this policy is to allow the use of
\fI\%add_custom_command()\fP SOURCE signatures.  The \fBNEW\fP behavior for this
policy is to issue an error if such a signature is used.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0049
.sp
Do not expand variables in target source entries.
.sp
CMake 2.8.12 and lower performed an extra layer of variable expansion
when evaluating source file names:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
set(a_source foo.c)
add_executable(foo \e${a_source})
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
This was undocumented behavior.
.sp
The \fBOLD\fP behavior for this policy is to expand such variables when processing
the target sources.  The \fBNEW\fP behavior for this policy is to issue an error
if such variables need to be expanded.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0048
.sp
The \fI\%project()\fP command manages \fBVERSION\fP variables.
.sp
CMake version 3.0 introduced the \fBVERSION\fP option of the \fI\%project()\fP
command to specify a project version as well as the name.  In order to keep
\fI\%PROJECT_VERSION\fP and related variables consistent with variable
\fI\%PROJECT_NAME\fP it is necessary to set the \fBVERSION\fP variables
to the empty string when no \fBVERSION\fP is given to \fI\%project()\fP\&.
However, this can change behavior for existing projects that set \fBVERSION\fP
variables themselves since \fI\%project()\fP may now clear them.
This policy controls the behavior for compatibility with such projects.
.sp
The \fBOLD\fP behavior for this policy is to leave \fBVERSION\fP variables untouched.
The \fBNEW\fP behavior for this policy is to set \fBVERSION\fP as documented by the
\fI\%project()\fP command.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0047
.sp
Use \fBQCC\fP compiler id for the qcc drivers on QNX.
.sp
CMake 3.0 and above recognize that the QNX qcc compiler driver is
different from the GNU compiler.
CMake now prefers to present this to projects by setting the
\fI\%CMAKE_<LANG>_COMPILER_ID\fP variable to \fBQCC\fP instead
of \fBGNU\fP\&.  However, existing projects may assume the compiler id for
QNX qcc is just \fBGNU\fP as it was in CMake versions prior to 3.0.
Therefore this policy determines for QNX qcc which compiler id to
report in the \fI\%CMAKE_<LANG>_COMPILER_ID\fP variable after
language \fB<LANG>\fP is enabled by the \fI\%project()\fP or
\fI\%enable_language()\fP command.  The policy must be set prior
to the invocation of either command.
.sp
The \fBOLD\fP behavior for this policy is to use the \fBGNU\fP compiler id
for the qcc and QCC compiler drivers. The \fBNEW\fP behavior for this policy
is to use the \fBQCC\fP compiler id for those drivers.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0047\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0046
.sp
Error on non\-existent dependency in add_dependencies.
.sp
CMake 2.8.12 and lower silently ignored non\-existent dependencies
listed in the \fI\%add_dependencies()\fP command.
.sp
The \fBOLD\fP behavior for this policy is to silently ignore non\-existent
dependencies. The \fBNEW\fP behavior for this policy is to report an error
if non\-existent dependencies are listed in the \fI\%add_dependencies()\fP
command.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0045
.sp
Error on non\-existent target in get_target_property.
.sp
In CMake 2.8.12 and lower, the \fI\%get_target_property()\fP command accepted
a non\-existent target argument without issuing any error or warning.  The
result variable is set to a \fB\-NOTFOUND\fP value.
.sp
The \fBOLD\fP behavior for this policy is to issue no warning and set the result
variable to a \fB\-NOTFOUND\fP value.  The \fBNEW\fP behavior
for this policy is to issue a \fBFATAL_ERROR\fP if the command is called with a
non\-existent target.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0044
.sp
Case sensitive \fB<LANG>_COMPILER_ID\fP generator expressions
.sp
CMake 2.8.12 introduced the \fB<LANG>_COMPILER_ID\fP
\fI\%generator expressions\fP to allow
comparison of the \fI\%CMAKE_<LANG>_COMPILER_ID\fP with a test value.  The
possible valid values are lowercase, but the comparison with the test value
was performed case\-insensitively.
.sp
The \fBOLD\fP behavior for this policy is to perform a case\-insensitive comparison
with the value in the \fB<LANG>_COMPILER_ID\fP expression. The \fBNEW\fP behavior
for this policy is to perform a case\-sensitive comparison with the value in
the \fB<LANG>_COMPILER_ID\fP expression.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0043
.sp
Ignore COMPILE_DEFINITIONS_<Config> properties
.sp
CMake 2.8.12 and lower allowed setting the
\fI\%COMPILE_DEFINITIONS_<CONFIG>\fP target property and
\fI\%COMPILE_DEFINITIONS_<CONFIG>\fP directory property to apply
configuration\-specific compile definitions.
.sp
Since CMake 2.8.10, the \fI\%COMPILE_DEFINITIONS\fP property has supported
\fI\%generator expressions\fP for setting
configuration\-dependent content.  The continued existence of the suffixed
variables is redundant, and causes a maintenance burden.  Population of the
\fI\%COMPILE_DEFINITIONS_DEBUG\fP property
may be replaced with a population of \fI\%COMPILE_DEFINITIONS\fP directly
or via \fI\%target_compile_definitions()\fP:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
# Old Interfaces:
set_property(TARGET tgt APPEND PROPERTY
  COMPILE_DEFINITIONS_DEBUG DEBUG_MODE
)
set_property(DIRECTORY APPEND PROPERTY
  COMPILE_DEFINITIONS_DEBUG DIR_DEBUG_MODE
)

# New Interfaces:
set_property(TARGET tgt APPEND PROPERTY
  COMPILE_DEFINITIONS $<$<CONFIG:Debug>:DEBUG_MODE>
)
target_compile_definitions(tgt PRIVATE $<$<CONFIG:Debug>:DEBUG_MODE>)
set_property(DIRECTORY APPEND PROPERTY
  COMPILE_DEFINITIONS $<$<CONFIG:Debug>:DIR_DEBUG_MODE>
)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
The \fBOLD\fP behavior for this policy is to consume the content of the suffixed
\fI\%COMPILE_DEFINITIONS_<CONFIG>\fP target property when generating the
compilation command. The \fBNEW\fP behavior for this policy is to ignore the content
of the \fI\%COMPILE_DEFINITIONS_<CONFIG>\fP target property .
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0042
.sp
\fI\%MACOSX_RPATH\fP is enabled by default.
.sp
CMake 2.8.12 and newer has support for using \fB@rpath\fP in a target\(aqs install
name.  This was enabled by setting the target property
\fI\%MACOSX_RPATH\fP\&.  The \fB@rpath\fP in an install name is a more
flexible and powerful mechanism than \fB@executable_path\fP or \fB@loader_path\fP
for locating shared libraries.
.sp
CMake 3.0 and later prefer this property to be ON by default.  Projects
wanting \fB@rpath\fP in a target\(aqs install name may remove any setting of
the \fI\%INSTALL_NAME_DIR\fP and \fI\%CMAKE_INSTALL_NAME_DIR\fP
variables.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0041
.sp
Error on relative include with generator expression.
.sp
Diagnostics in CMake 2.8.12 and lower silently ignored an entry in the
\fI\%INTERFACE_INCLUDE_DIRECTORIES\fP of a target if it contained a generator
expression at any position.
.sp
The path entries in that target property should not be relative. High\-level
API should ensure that by adding either a source directory or a install
directory prefix, as appropriate.
.sp
As an additional diagnostic, the \fI\%INTERFACE_INCLUDE_DIRECTORIES\fP generated
on an \fI\%IMPORTED\fP target for the install location should not contain
paths in the source directory or the build directory.
.sp
The \fBOLD\fP behavior for this policy is to ignore relative path entries if they
contain a generator expression. The \fBNEW\fP behavior for this policy is to report
an error if a generator expression appears in another location and the path is
relative.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0040
.sp
The target in the \fBTARGET\fP signature of \fI\%add_custom_command()\fP
must exist and must be defined in the current directory.
.sp
CMake 2.8.12 and lower silently ignored a custom command created with
the \fBTARGET\fP signature of \fI\%add_custom_command()\fP
if the target is unknown or was defined outside the current directory.
.sp
The \fBOLD\fP behavior for this policy is to ignore custom commands
for unknown targets.  The \fBNEW\fP behavior for this policy is to report
an error if the target referenced in \fI\%add_custom_command()\fP is
unknown or was defined outside the current directory.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0039
.sp
Utility targets may not have link dependencies.
.sp
CMake 2.8.12 and lower allowed using utility targets in the left hand side
position of the \fI\%target_link_libraries()\fP command. This is an indicator
of a bug in user code.
.sp
The \fBOLD\fP behavior for this policy is to ignore attempts to set the link
libraries of utility targets.  The \fBNEW\fP behavior for this policy is to
report an error if an attempt is made to set the link libraries of a
utility target.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0038
.sp
Targets may not link directly to themselves.
.sp
CMake 2.8.12 and lower allowed a build target to link to itself directly with
a \fI\%target_link_libraries()\fP call. This is an indicator of a bug in
user code.
.sp
The \fBOLD\fP behavior for this policy is to ignore targets which list themselves
in their own link implementation.  The \fBNEW\fP behavior for this policy is to
report an error if a target attempts to link to itself.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0037
.sp
Target names should not be reserved and should match a validity pattern.
.sp
CMake 2.8.12 and lower allowed creating targets using \fI\%add_library()\fP,
\fI\%add_executable()\fP and \fI\%add_custom_target()\fP with unrestricted
choice for the target name.  Newer cmake features such
as \fI\%cmake\-generator\-expressions(7)\fP and some
diagnostics expect target names to match a restricted pattern.
.sp
Target names may contain upper and lower case letters, numbers, the underscore
character (\fB_\fP), dot(\fB\&.\fP), plus(\fB+\fP) and minus(\fB\-\fP).
As a special case, \fBALIAS\fP and \fBIMPORTED\fP targets may contain
two consecutive colons.
.sp
Target names reserved by one or more CMake generators are not allowed.
Among others these include \fBall\fP, \fBclean\fP, \fBhelp\fP, and \fBinstall\fP\&.
.sp
Target names associated with optional features, such as \fBtest\fP and
\fBpackage\fP, may also be reserved.  CMake 3.10 and below always reserve them.
CMake 3.11 and above reserve them only when the corresponding feature is
enabled (e.g. by including the \fI\%CTest\fP or \fI\%CPack\fP modules).
.sp
The \fBOLD\fP behavior for this policy is to allow creating targets with
reserved names or which do not match the validity pattern.
The \fBNEW\fP behavior for this policy is to report an error
if an add_* command is used with an invalid target name.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0036
.sp
The \fI\%build_name()\fP command should not be called.
.sp
This command was added in May 2001 to compute a name for the current
operating system and compiler combination.  The command has long been
documented as discouraged and replaced by the \fI\%CMAKE_SYSTEM\fP
and \fI\%CMAKE_<LANG>_COMPILER\fP variables.
.sp
CMake >= 3.0 prefer that this command never be called.
The \fBOLD\fP behavior for this policy is to allow the command to be called.
The \fBNEW\fP behavior for this policy is to issue a \fBFATAL_ERROR\fP when the
command is called.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0035
.sp
The \fI\%variable_requires()\fP command should not be called.
.sp
This command was introduced in November 2001 to perform some conditional
logic.  It has long been replaced by the \fI\%if()\fP command.
.sp
CMake >= 3.0 prefer that this command never be called.
The \fBOLD\fP behavior for this policy is to allow the command to be called.
The \fBNEW\fP behavior for this policy is to issue a \fBFATAL_ERROR\fP when the
command is called.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0034
.sp
The \fI\%utility_source()\fP command should not be called.
.sp
This command was introduced in March 2001 to help build executables used to
generate other files.  This approach has long been replaced by
\fI\%add_executable()\fP combined with \fI\%add_custom_command()\fP\&.
.sp
CMake >= 3.0 prefer that this command never be called.
The \fBOLD\fP behavior for this policy is to allow the command to be called.
The \fBNEW\fP behavior for this policy is to issue a \fBFATAL_ERROR\fP when the
command is called.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0033
.sp
The \fI\%export_library_dependencies()\fP command should not be called.
.sp
This command was added in January 2003 to export \fB<tgt>_LIB_DEPENDS\fP
internal CMake cache entries to a file for installation with a project.
This was used at the time to allow transitive link dependencies to
work for applications outside of the original build tree of a project.
The functionality has been superseded by the \fI\%export()\fP and
\fI\%install(EXPORT)\fP commands.
.sp
CMake >= 3.0 prefer that this command never be called.
The \fBOLD\fP behavior for this policy is to allow the command to be called.
The \fBNEW\fP behavior for this policy is to issue a \fBFATAL_ERROR\fP when the
command is called.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0032
.sp
The \fI\%output_required_files()\fP command should not be called.
.sp
This command was added in June 2001 to expose the then\-current CMake
implicit dependency scanner.  CMake\(aqs real implicit dependency scanner
has evolved since then but is not exposed through this command.  The
scanning capabilities of this command are very limited and this
functionality is better achieved through dedicated outside tools.
.sp
CMake >= 3.0 prefer that this command never be called.
The \fBOLD\fP behavior for this policy is to allow the command to be called.
The \fBNEW\fP behavior for this policy is to issue a \fBFATAL_ERROR\fP when the
command is called.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0031
.sp
The \fI\%load_command()\fP command should not be called.
.sp
This command was added in August 2002 to allow projects to add
arbitrary commands implemented in C or C++.  However, it does
not work when the toolchain in use does not match the ABI of
the CMake process.  It has been mostly superseded by the
\fI\%macro()\fP and \fI\%function()\fP commands.
.sp
CMake >= 3.0 prefer that this command never be called.
The \fBOLD\fP behavior for this policy is to allow the command to be called.
The \fBNEW\fP behavior for this policy is to issue a \fBFATAL_ERROR\fP when the
command is called.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0030
.sp
The \fI\%use_mangled_mesa()\fP command should not be called.
.sp
This command was created in September 2001 to support VTK before
modern CMake language and custom command capabilities.  VTK has
not used it in years.
.sp
CMake >= 3.0 prefer that this command never be called.
The \fBOLD\fP behavior for this policy is to allow the command to be called.
The \fBNEW\fP behavior for this policy is to issue a \fBFATAL_ERROR\fP when the
command is called.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0029
.sp
The \fI\%subdir_depends()\fP command should not be called.
.sp
The implementation of this command has been empty since December 2001
but was kept in CMake for compatibility for a long time.
.sp
CMake >= 3.0 prefer that this command never be called.
The \fBOLD\fP behavior for this policy is to allow the command to be called.
The \fBNEW\fP behavior for this policy is to issue a \fBFATAL_ERROR\fP when the
command is called.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0028
.sp
Double colon in target name means \fBALIAS\fP or \fBIMPORTED\fP target.
.sp
CMake 2.8.12 and lower allowed the use of targets and files with double
colons in \fI\%target_link_libraries()\fP, with some buildsystem generators.
.sp
The use of double\-colons is a common pattern used to namespace \fBIMPORTED\fP
targets and \fBALIAS\fP targets.  When computing the link dependencies of
a target, the name of each dependency could either be a target, or a file
on disk.  Previously, if a target was not found with a matching name, the name
was considered to refer to a file on disk.  This can lead to confusing error
messages if there is a typo in what should be a target name.
.sp
See also the \fI\%LINK_LIBRARIES_ONLY_TARGETS\fP target property.
.sp
The \fBOLD\fP behavior for this policy is to search for targets, then files on
disk, even if the search term contains double\-colons.  The \fBNEW\fP behavior
for this policy is to issue a \fBFATAL_ERROR\fP if a link dependency contains
double\-colons but is not an \fBIMPORTED\fP target or an \fBALIAS\fP target.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0027
.sp
Conditionally linked imported targets with missing include directories.
.sp
CMake 2.8.11 introduced introduced the concept of
\fI\%INTERFACE_INCLUDE_DIRECTORIES\fP, and a check at cmake time that the
entries in the \fI\%INTERFACE_INCLUDE_DIRECTORIES\fP of an \fBIMPORTED\fP
target actually exist.  CMake 2.8.11 also introduced generator expression
support in the \fI\%target_link_libraries()\fP command.  However, if an
imported target is linked as a result of a generator expression evaluation, the
entries in the \fI\%INTERFACE_INCLUDE_DIRECTORIES\fP of that target were not
checked for existence as they should be.
.sp
The \fBOLD\fP behavior of this policy is to report a warning if an entry in
the \fI\%INTERFACE_INCLUDE_DIRECTORIES\fP of a generator\-expression
conditionally linked \fBIMPORTED\fP target does not exist.
.sp
The \fBNEW\fP behavior of this policy is to report an error if an entry in
the \fI\%INTERFACE_INCLUDE_DIRECTORIES\fP of a generator\-expression
conditionally linked \fBIMPORTED\fP target does not exist.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0026
.sp
Disallow use of the LOCATION property for build targets.
.sp
CMake 2.8.12 and lower allowed reading the \fI\%LOCATION\fP target
property (and configuration\-specific variants) to
determine the eventual location of build targets.  This relies on the
assumption that all necessary information is available at
configure\-time to determine the final location and filename of the
target.  However, this property is not fully determined until later at
generate\-time.  At generate time, the \fI\%$<TARGET_FILE>\fP generator
expression can be used to determine the eventual \fI\%LOCATION\fP of a target
output.
.sp
Code which reads the \fI\%LOCATION\fP target property can be ported to
use the \fI\%$<TARGET_FILE>\fP generator expression together with the
\fI\%file(GENERATE)\fP subcommand to generate a file containing
the target location.
.sp
The \fBOLD\fP behavior for this policy is to allow reading the \fI\%LOCATION\fP
properties from build\-targets.  The \fBNEW\fP behavior for this policy is to
not to allow reading the \fI\%LOCATION\fP properties from build\-targets.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0025
.sp
Compiler id for Apple Clang is now \fBAppleClang\fP\&.
.sp
CMake 3.0 and above recognize that Apple Clang is a different compiler
than upstream Clang and that they have different version numbers.
CMake now prefers to present this to projects by setting the
\fI\%CMAKE_<LANG>_COMPILER_ID\fP variable to \fBAppleClang\fP instead
of \fBClang\fP\&.  However, existing projects may assume the compiler id for
Apple Clang is just \fBClang\fP as it was in CMake versions prior to 3.0.
Therefore this policy determines for Apple Clang which compiler id to
report in the \fI\%CMAKE_<LANG>_COMPILER_ID\fP variable after
language \fB<LANG>\fP is enabled by the \fI\%project()\fP or
\fI\%enable_language()\fP command.  The policy must be set prior
to the invocation of either command.
.sp
The \fBOLD\fP behavior for this policy is to use compiler id \fBClang\fP\&.  The
\fBNEW\fP behavior for this policy is to use compiler id \fBAppleClang\fP\&.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake does \fInot\fP warn by default, and uses \fBOLD\fP behavior.
.sp
See documentation of the
\fI\%CMAKE_POLICY_WARNING_CMP0025\fP
variable to control the warning.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0024
.sp
Disallow include export result.
.sp
CMake 2.8.12 and lower allowed use of the \fI\%include()\fP command with the
result of the \fI\%export()\fP command.  This relies on the assumption that
the \fI\%export()\fP command has an immediate effect at configure\-time during
a cmake run.  Certain properties of targets are not fully determined
until later at generate\-time, such as the link language and complete
list of link libraries.  Future refactoring will change the effect of
the \fI\%export()\fP command to be executed at generate\-time.  Use \fBALIAS\fP
targets instead in cases where the goal is to refer to targets by
another name.
.sp
The \fBOLD\fP behavior for this policy is to allow including the result of
an \fI\%export()\fP command.  The \fBNEW\fP behavior for this policy is not to
allow including the result of an \fI\%export()\fP command.
.sp
This policy was introduced in CMake version 3.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 2.8
.SS CMP0023
.sp
Plain and keyword \fI\%target_link_libraries()\fP signatures cannot be mixed.
.sp
CMake 2.8.12 introduced the \fI\%target_link_libraries()\fP signature using
the \fBPUBLIC\fP, \fBPRIVATE\fP, and \fBINTERFACE\fP keywords to generalize the
\fBLINK_PUBLIC\fP and \fBLINK_PRIVATE\fP keywords introduced in CMake 2.8.7.
Use of signatures with any of these keywords sets the link interface of a
target explicitly, even if empty.  This produces confusing behavior
when used in combination with the historical behavior of the plain
\fI\%target_link_libraries()\fP signature.  For example, consider the code:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
target_link_libraries(mylib A)
target_link_libraries(mylib PRIVATE B)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
After the first line the link interface has not been set explicitly so
CMake would use the link implementation, A, as the link interface.
However, the second line sets the link interface to empty.  In order
to avoid this subtle behavior CMake now prefers to disallow mixing the
plain and keyword signatures of \fI\%target_link_libraries()\fP for a single
target.
.sp
The \fBOLD\fP behavior for this policy is to allow keyword and plain
\fI\%target_link_libraries()\fP signatures to be mixed.  The \fBNEW\fP behavior for
this policy is to not to allow mixing of the keyword and plain
signatures.
.sp
This policy was introduced in CMake version 2.8.12\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0022
.sp
\fI\%INTERFACE_LINK_LIBRARIES\fP defines the link interface.
.sp
CMake 2.8.11 constructed the \(aqlink interface\(aq of a target from
properties matching \fB(IMPORTED_)?LINK_INTERFACE_LIBRARIES(_<CONFIG>)?\fP\&.
The modern way to specify config\-sensitive content is to use generator
expressions and the \fBIMPORTED_\fP prefix makes uniform processing of the
link interface with generator expressions impossible.  The
\fI\%INTERFACE_LINK_LIBRARIES\fP target property was introduced as a
replacement in CMake 2.8.12.  This new property is named consistently
with the \fBINTERFACE_COMPILE_DEFINITIONS\fP, \fBINTERFACE_INCLUDE_DIRECTORIES\fP
and \fBINTERFACE_COMPILE_OPTIONS\fP properties.  For in\-build targets, CMake
will use the INTERFACE_LINK_LIBRARIES property as the source of the
link interface only if policy \fBCMP0022\fP is \fBNEW\fP\&.  When exporting a target
which has this policy set to \fBNEW\fP, only the \fI\%INTERFACE_LINK_LIBRARIES\fP
property will be processed and generated for the \fBIMPORTED\fP target by
default.  A new option to the \fI\%install(EXPORT)\fP and export commands
allows export of the old\-style properties for compatibility with
downstream users of CMake versions older than 2.8.12.  The
\fI\%target_link_libraries()\fP command will no longer populate the properties
matching \fBLINK_INTERFACE_LIBRARIES(_<CONFIG>)?\fP if this policy is \fBNEW\fP\&.
.sp
Warning\-free future\-compatible code which works with CMake 2.8.7 onwards
can be written by using the \fBLINK_PRIVATE\fP and \fBLINK_PUBLIC\fP keywords
of \fI\%target_link_libraries()\fP\&.
.sp
The \fBOLD\fP behavior for this policy is to ignore the
\fI\%INTERFACE_LINK_LIBRARIES\fP property for in\-build targets.
The \fBNEW\fP behavior for this policy is to use the \fBINTERFACE_LINK_LIBRARIES\fP
property for in\-build targets, and ignore the old properties matching
\fB(IMPORTED_)?LINK_INTERFACE_LIBRARIES(_<CONFIG>)?\fP\&.
.sp
This policy was introduced in CMake version 2.8.12\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0021
.sp
Fatal error on relative paths in \fI\%INCLUDE_DIRECTORIES\fP target
property.
.sp
CMake 2.8.10.2 and lower allowed the \fI\%INCLUDE_DIRECTORIES\fP target
property to contain relative paths.  The base path for such relative
entries is not well defined.  CMake 2.8.12 issues a \fBFATAL_ERROR\fP if the
\fI\%INCLUDE_DIRECTORIES\fP property contains a relative path.
.sp
The \fBOLD\fP behavior for this policy is not to warn about relative paths
in the \fBINCLUDE_DIRECTORIES\fP target property.  The \fBNEW\fP behavior for this
policy is to issue a \fBFATAL_ERROR\fP if \fBINCLUDE_DIRECTORIES\fP contains a
relative path.
.sp
This policy was introduced in CMake version 2.8.12\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0020
.sp
Automatically link Qt executables to \fBqtmain\fP target on Windows.
.sp
CMake 2.8.10 and lower required users of Qt to always specify a link
dependency to the \fBqtmain.lib\fP static library manually on Windows.
CMake 2.8.11 gained the ability to evaluate generator expressions
while determining the link dependencies from \fBIMPORTED\fP targets.  This
allows CMake itself to automatically link executables which link to Qt
to the \fBqtmain.lib\fP library when using \fBIMPORTED\fP Qt targets.  For
applications already linking to \fBqtmain.lib\fP, this should have little
impact.  For applications which supply their own alternative WinMain
implementation and for applications which use the QAxServer library,
this automatic linking will need to be disabled as per the
documentation.
.sp
The \fBOLD\fP behavior for this policy is not to link executables to
\fBqtmain.lib\fP automatically when they link to the QtCore \fBIMPORTED\fP target.
The \fBNEW\fP behavior for this policy is to link executables to \fBqtmain.lib\fP
automatically when they link to QtCore \fBIMPORTED\fP target.
.sp
This policy was introduced in CMake version 2.8.11\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0019
.sp
Do not re\-expand variables in include and link information.
.sp
CMake 2.8.10 and lower re\-evaluated values given to the
include_directories, link_directories, and link_libraries commands to
expand any leftover variable references at the end of the
configuration step.  This was for strict compatibility with VERY early
CMake versions because all variable references are now normally
evaluated during CMake language processing.  CMake 2.8.11 and higher
prefer to skip the extra evaluation.
.sp
The \fBOLD\fP behavior for this policy is to re\-evaluate the values for
strict compatibility.  The \fBNEW\fP behavior for this policy is to leave
the values untouched.
.sp
This policy was introduced in CMake version 2.8.11\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0018
.sp
Ignore \fBCMAKE_SHARED_LIBRARY_<Lang>_FLAGS\fP variable.
.sp
CMake 2.8.8 and lower compiled sources in \fBSHARED\fP and \fBMODULE\fP libraries
using the value of the undocumented \fBCMAKE_SHARED_LIBRARY_<Lang>_FLAGS\fP
platform variable.  The variable contained platform\-specific flags
needed to compile objects for shared libraries.  Typically it included
a flag such as \fB\-fPIC\fP for position independent code but also included
other flags needed on certain platforms.  CMake 2.8.9 and higher
prefer instead to use the \fI\%POSITION_INDEPENDENT_CODE\fP target
property to determine what targets should be position independent, and new
undocumented platform variables to select flags while ignoring
\fBCMAKE_SHARED_LIBRARY_<Lang>_FLAGS\fP completely.
.sp
The default for either approach produces identical compilation flags,
but if a project modifies \fBCMAKE_SHARED_LIBRARY_<Lang>_FLAGS\fP from its
original value this policy determines which approach to use.
.sp
The \fBOLD\fP behavior for this policy is to ignore the
\fI\%POSITION_INDEPENDENT_CODE\fP property for all targets and use the
modified value of \fBCMAKE_SHARED_LIBRARY_<Lang>_FLAGS\fP for \fBSHARED\fP and
\fBMODULE\fP libraries.
.sp
The \fBNEW\fP behavior for this policy is to ignore
\fBCMAKE_SHARED_LIBRARY_<Lang>_FLAGS\fP whether it is modified or not and
honor the \fI\%POSITION_INDEPENDENT_CODE\fP target property.
.sp
This policy was introduced in CMake version 2.8.9\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0017
.sp
Prefer files from the CMake module directory when including from there.
.sp
Starting with CMake 2.8.4, if a cmake\-module shipped with CMake (i.e.
located in the CMake module directory) calls \fI\%include()\fP or
\fI\%find_package()\fP, the files located in the CMake module directory are
preferred over the files in \fI\%CMAKE_MODULE_PATH\fP\&.  This makes sure
that the modules belonging to CMake always get those files included which
they expect, and against which they were developed and tested.  In all
other cases, the files found in \fI\%CMAKE_MODULE_PATH\fP still take
precedence over the ones in the CMake module directory.  The \fBOLD\fP
behavior is to always prefer files from CMAKE_MODULE_PATH over files
from the CMake modules directory.
.sp
This policy was introduced in CMake version 2.8.4\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0016
.sp
\fI\%target_link_libraries()\fP reports error if its only argument
is not a target.
.sp
In CMake 2.8.2 and lower the \fI\%target_link_libraries()\fP command silently
ignored if it was called with only one argument, and this argument
wasn\(aqt a valid target.  In CMake 2.8.3 and above it reports an error
in this case.
.sp
This policy was introduced in CMake version 2.8.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0015
.INDENT 0.0
.INDENT 3.5
\fI\%link_directories()\fP treats paths relative to the source dir.
.UNINDENT
.UNINDENT
.sp
In CMake 2.8.0 and lower the \fI\%link_directories()\fP command passed
relative paths unchanged to the linker.  In CMake 2.8.1 and above the
\fI\%link_directories()\fP command prefers to interpret relative paths with
respect to \fBCMAKE_CURRENT_SOURCE_DIR\fP, which is consistent with
\fI\%include_directories()\fP and other commands.  The \fBOLD\fP behavior for
this policy is to use relative paths verbatim in the linker command.  The
\fBNEW\fP behavior for this policy is to convert relative paths to absolute
paths by appending the relative path to \fBCMAKE_CURRENT_SOURCE_DIR\fP\&.
.sp
This policy was introduced in CMake version 2.8.1\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0014
.sp
Input directories must have \fBCMakeLists.txt\fP\&.
.sp
CMake versions before 2.8 silently ignored missing \fBCMakeLists.txt\fP
files in directories referenced by \fI\%add_subdirectory()\fP or  \fI\%subdirs()\fP,
treating them as if present but empty.  In CMake 2.8.0 and above this
\fI\%cmake_policy()\fP determines whether or not the case is an error.
The \fBOLD\fP behavior for this policy is to silently ignore the problem.
The \fBNEW\fP behavior for this policy is to report an error.
.sp
This policy was introduced in CMake version 2.8.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0013
.sp
Duplicate binary directories are not allowed.
.sp
CMake 2.6.3 and below silently permitted add_subdirectory() calls to
create the same binary directory multiple times.  During build system
generation files would be written and then overwritten in the build
tree and could lead to strange behavior.  CMake 2.6.4 and above
explicitly detect duplicate binary directories.  CMake 2.6.4 always
considers this case an error.  In CMake 2.8.0 and above this policy
determines whether or not the case is an error.  The \fBOLD\fP behavior for
this policy is to allow duplicate binary directories.  The NEW
behavior for this policy is to disallow duplicate binary directories
with an error.
.sp
This policy was introduced in CMake version 2.8.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0012
.sp
\fI\%if()\fP recognizes numbers and boolean constants.
.sp
In CMake versions 2.6.4 and lower the \fI\%if()\fP command implicitly
dereferenced arguments corresponding to variables, even those named
like numbers or boolean constants, except for \fB0\fP and \fB1\fP\&.  Numbers and
boolean constants such as \fBtrue\fP, \fBfalse\fP, \fByes\fP, \fBno\fP, \fBon\fP,
\fBoff\fP, \fBy\fP, \fBn\fP, \fBnotfound\fP, \fBignore\fP (all case insensitive)
were recognized in some cases but not all.  For example, the code \fBif(TRUE)\fP
might have evaluated as \fBfalse\fP\&.
Numbers such as 2 were recognized only in boolean expressions
like \fBif(NOT 2)\fP (leading to \fBfalse\fP) but not as a single\-argument like
\fBif(2)\fP (also leading to \fBfalse\fP).  Later versions of CMake prefer to
treat numbers and boolean constants literally, so they should not be
used as variable names.
.sp
The \fBOLD\fP behavior for this policy is to implicitly dereference
variables named like numbers and boolean constants.  The \fBNEW\fP behavior
for this policy is to recognize numbers and boolean constants without
dereferencing variables with such names.
.sp
This policy was introduced in CMake version 2.8.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SH POLICIES INTRODUCED BY CMAKE 2.6
.SS CMP0011
.sp
Included scripts do automatic \fI\%cmake_policy()\fP PUSH and POP.
.sp
In CMake 2.6.2 and below, CMake Policy settings in scripts loaded by
the \fI\%include()\fP and \fI\%find_package()\fP commands would affect
the includer.  Explicit invocations of \fBcmake_policy(PUSH)\fP and
\fBcmake_policy(POP)\fP were required to isolate policy changes and protect
the includer.  While some scripts intend to affect the policies of their
includer, most do not.  In CMake 2.6.3 and above, \fI\%include()\fP and
\fI\%find_package()\fP by default \fBPUSH\fP and \fBPOP\fP an entry on
the policy stack around an included
script, but provide a \fBNO_POLICY_SCOPE\fP option to disable it.  This
policy determines whether or not to imply \fBNO_POLICY_SCOPE\fP for
compatibility.  The \fBOLD\fP behavior for this policy is to imply
\fBNO_POLICY_SCOPE\fP for \fI\%include()\fP and \fI\%find_package()\fP commands.
The \fBNEW\fP behavior for this policy is to allow the commands to do
their default cmake_policy \fBPUSH\fP and \fBPOP\fP\&.
.sp
This policy was introduced in CMake version 2.6.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0010
.sp
Bad variable reference syntax is an error.
.sp
In CMake 2.6.2 and below, incorrect variable reference syntax such as
a missing close\-brace (\fB${FOO\fP) was reported but did not stop
processing of CMake code.  This policy determines whether a bad
variable reference is an error.  The \fBOLD\fP behavior for this policy is
to warn about the error, leave the string untouched, and continue.
The \fBNEW\fP behavior for this policy is to report an error.
.sp
If \fI\%CMP0053\fP is set to \fBNEW\fP, this policy has no effect
and is treated as always being \fBNEW\fP\&.
.sp
This policy was introduced in CMake version 2.6.3\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0009
.sp
FILE GLOB_RECURSE calls should not follow symlinks by default.
.sp
In CMake 2.6.1 and below, \fI\%file(GLOB_RECURSE)\fP calls would follow
through symlinks, sometimes coming up with unexpectedly large result sets
because of symlinks to top level directories that contain hundreds of
thousands of files.
.sp
This policy determines whether or not to follow symlinks encountered
during a \fI\%file(GLOB_RECURSE)\fP call.  The \fBOLD\fP behavior for this
policy is to follow the symlinks.  The \fBNEW\fP behavior for this policy is not
to follow the symlinks by default, but only if \fBFOLLOW_SYMLINKS\fP is given
as an additional argument to the \fBFILE\fP command.
.sp
This policy was introduced in CMake version 2.6.2\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0008
.sp
Libraries linked by full\-path must have a valid library file name.
.sp
In CMake 2.4 and below it is possible to write code like
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
target_link_libraries(myexe /full/path/to/somelib)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
where \fBsomelib\fP is supposed to be a valid library file name such as
\fBlibsomelib.a\fP or \fBsomelib.lib\fP\&.  For Makefile generators this
produces an error at build time because the dependency on the full
path cannot be found.  For \fI\%Visual Studio Generators\fP IDE
and \fI\%Xcode\fP generators this used to
work by accident because CMake would always split off the library
directory and ask the linker to search for the library by name
(\fB\-lsomelib\fP or \fBsomelib.lib\fP).  Despite the failure with Makefiles, some
projects have code like this and build only with Visual Studio and/or Xcode.
This version of CMake prefers to pass the full path directly to the
native build tool, which will fail in this case because it does not
name a valid library file.
.sp
This policy determines what to do with full paths that do not appear
to name a valid library file.  The \fBOLD\fP behavior for this policy is to
split the library name from the path and ask the linker to search for
it.  The \fBNEW\fP behavior for this policy is to trust the given path and
pass it directly to the native build tool unchanged.
.sp
This policy was introduced in CMake version 2.6.1\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0007
.sp
list command no longer ignores empty elements.
.sp
This policy determines whether the list command will ignore empty
elements in the list.  CMake 2.4 and below list commands ignored all
empty elements in the list.  For example, \fBa;b;;c\fP would have length 3
and not 4.  The \fBOLD\fP behavior for this policy is to ignore empty list
elements.  The \fBNEW\fP behavior for this policy is to correctly count
empty elements in a list.
.sp
This policy was introduced in CMake version 2.6.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0006
.sp
Installing \fI\%MACOSX_BUNDLE\fP targets requires a \fBBUNDLE DESTINATION\fP\&.
.sp
This policy determines whether the \fI\%install(TARGETS)\fP command must be
given a \fBBUNDLE DESTINATION\fP when asked to install a target with the
\fI\%MACOSX_BUNDLE\fP property set.  CMake 2.4 and below did not distinguish
application bundles from normal executables when installing targets.
CMake 2.6 provides a \fBBUNDLE\fP option to the \fI\%install(TARGETS)\fP
command that specifies rules specific to application bundles on the Mac.
Projects should use this option when installing a target with the
\fI\%MACOSX_BUNDLE\fP property set.
.sp
The \fBOLD\fP behavior for this policy is to fall back to the
\fBRUNTIME DESTINATION\fP if a \fBBUNDLE DESTINATION\fP is not given.  The \fBNEW\fP
behavior for this policy is to produce an error if a bundle target is installed
without a \fBBUNDLE DESTINATION\fP\&.
.sp
This policy was introduced in CMake version 2.6.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0005
.sp
Preprocessor definition values are now escaped automatically.
.sp
This policy determines whether or not CMake should generate escaped
preprocessor definition values added via add_definitions.  CMake
versions 2.4 and below assumed that only trivial values would be given
for macros in add_definitions calls.  It did not attempt to escape
non\-trivial values such as string literals in generated build rules.
CMake versions 2.6 and above support escaping of most values, but
cannot assume the user has not added escapes already in an attempt to
work around limitations in earlier versions.
.sp
The \fBOLD\fP behavior for this policy is to place definition values given
to add_definitions directly in the generated build rules without
attempting to escape anything.  The \fBNEW\fP behavior for this policy is to
generate correct escapes for all native build tools automatically.
See documentation of the \fBCOMPILE_DEFINITIONS\fP target property for
limitations of the escaping implementation.
.sp
This policy was introduced in CMake version 2.6.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0004
.sp
Libraries linked may not have leading or trailing whitespace.
.sp
CMake versions 2.4 and below silently removed leading and trailing
whitespace from libraries linked with code like
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
target_link_libraries(myexe \(dq A \(dq)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
This could lead to subtle errors in user projects.
.sp
The \fBOLD\fP behavior for this policy is to silently remove leading and
trailing whitespace.  The \fBNEW\fP behavior for this policy is to diagnose
the existence of such whitespace as an error.  The setting for this
policy used when checking the library names is that in effect when the
target is created by an \fI\%add_executable()\fP or \fI\%add_library()\fP
command.
.sp
This policy was introduced in CMake version 2.6.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0003
.sp
Libraries linked via full path no longer produce linker search paths.
.sp
This policy affects how libraries whose full paths are NOT known are
found at link time, but was created due to a change in how CMake deals
with libraries whose full paths are known.  Consider the code
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
target_link_libraries(myexe /path/to/libA.so)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
CMake 2.4 and below implemented linking to libraries whose full paths
are known by splitting them on the link line into separate components
consisting of the linker search path and the library name.  The
example code might have produced something like
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
\&... \-L/path/to \-lA ...
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
in order to link to library A.  An analysis was performed to order
multiple link directories such that the linker would find library A in
the desired location, but there are cases in which this does not work.
CMake versions 2.6 and above use the more reliable approach of passing
the full path to libraries directly to the linker in most cases.  The
example code now produces something like
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
\&... /path/to/libA.so ....
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Unfortunately this change can break code like
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
target_link_libraries(myexe /path/to/libA.so B)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
where \fBB\fP is meant to find \fB/path/to/libB.so\fP\&.  This code is wrong
because the user is asking the linker to find library B but has not
provided a linker search path (which may be added with the
link_directories command).  However, with the old linking
implementation the code would work accidentally because the linker
search path added for library A allowed library B to be found.
.sp
In order to support projects depending on linker search paths added by
linking to libraries with known full paths, the \fBOLD\fP behavior for this
policy will add the linker search paths even though they are not
needed for their own libraries.  When this policy is set to \fBOLD\fP, CMake
will produce a link line such as
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
\&... \-L/path/to /path/to/libA.so \-lB ...
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
which will allow library B to be found as it was previously.  When
this policy is set to NEW, CMake will produce a link line such as
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
\&... /path/to/libA.so \-lB ...
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
which more accurately matches what the project specified.
.sp
The setting for this policy used when generating the link line is that
in effect when the target is created by an add_executable or
add_library command.  For the example described above, the code
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_policy(SET CMP0003 OLD) # or cmake_policy(VERSION 2.4)
add_executable(myexe myexe.c)
target_link_libraries(myexe /path/to/libA.so B)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
will work and suppress the warning for this policy.  It may also be
updated to work with the corrected linking approach:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_policy(SET CMP0003 NEW) # or cmake_policy(VERSION 2.6)
link_directories(/path/to) # needed to find library B
add_executable(myexe myexe.c)
target_link_libraries(myexe /path/to/libA.so B)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
Even better, library B may be specified with a full path:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
add_executable(myexe myexe.c)
target_link_libraries(myexe /path/to/libA.so /path/to/libB.so)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
When all items on the link line have known paths CMake does not check
this policy so it has no effect.
.sp
Note that the warning for this policy will be issued for at most one
target.  This avoids flooding users with messages for every target
when setting the policy once will probably fix all targets.
.sp
This policy was introduced in CMake version 2.6.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0002
.sp
Logical target names must be globally unique.
.sp
Targets names created with \fI\%add_executable()\fP, \fI\%add_library()\fP, or
\fI\%add_custom_target()\fP are logical build target names.  Logical target
names must be globally unique because:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
\- Unique names may be referenced unambiguously both in CMake
  code and on make tool command lines.
\- Logical names are used by Xcode and VS IDE generators
  to produce meaningful project names for the targets.
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
The logical name of executable and library targets does not have to
correspond to the physical file names built.  Consider using the
\fI\%OUTPUT_NAME\fP target property to create two targets with the same
physical name while keeping logical names distinct.  Custom targets
must simply have globally unique names (unless one uses the global
property \fI\%ALLOW_DUPLICATE_CUSTOM_TARGETS\fP with a Makefiles generator).
.sp
This policy was introduced in CMake version 2.6.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0001
.sp
\fBCMAKE_BACKWARDS_COMPATIBILITY\fP should no longer be used.
.sp
The behavior is to check \fBCMAKE_BACKWARDS_COMPATIBILITY\fP and present
it to the user.  The \fBNEW\fP behavior is to ignore
CMAKE_BACKWARDS_COMPATIBILITY completely.
.sp
In CMake 2.4 and below the variable \fBCMAKE_BACKWARDS_COMPATIBILITY\fP was
used to request compatibility with earlier versions of CMake.  In
CMake 2.6 and above all compatibility issues are handled by policies
and the \fI\%cmake_policy()\fP command.  However, CMake must still check
\fBCMAKE_BACKWARDS_COMPATIBILITY\fP for projects written for CMake 2.4 and
below.
.sp
This policy was introduced in CMake version 2.6.0\&.
It may be set by \fI\%cmake_policy()\fP or \fI\%cmake_minimum_required()\fP\&.
If it is not set, CMake warns, and uses \fBOLD\fP behavior.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
.UNINDENT
.UNINDENT
.SS CMP0000
.sp
A minimum required CMake version must be specified.
.sp
CMake requires that projects specify the version of CMake to which
they have been written.  This policy has been put in place so users
trying to build the project may be told when they need to update their
CMake.  Specifying a version also helps the project build with CMake
versions newer than that specified.  Use the \fI\%cmake_minimum_required()\fP
command at the top of your main \fBCMakeLists.txt\fP file:
.INDENT 0.0
.INDENT 3.5
.sp
.nf
.ft C
cmake_minimum_required(VERSION <major>.<minor>)
.ft P
.fi
.UNINDENT
.UNINDENT
.sp
where \fB<major>.<minor>\fP is the version of CMake you want to support
(such as \fB3.14\fP).  The command will ensure that at least the given
version of CMake is running and help newer versions be compatible with
the project.  See documentation of \fI\%cmake_minimum_required()\fP for
details.
.sp
Note that the command invocation must appear in the \fBCMakeLists.txt\fP
file itself; a call in an included file is not sufficient.  However,
the  \fI\%cmake_policy()\fP command may be called to set policy \fBCMP0000\fP
to \fBOLD\fP or \fBNEW\fP behavior explicitly.  The \fBOLD\fP behavior is to
silently ignore the missing invocation.  The \fBNEW\fP behavior is to issue
an error instead of a warning.  An included file may set \fBCMP0000\fP
explicitly to affect how this policy is enforced for the main
\fBCMakeLists.txt\fP file.
.sp
This policy was introduced in CMake version 2.6.0.
.sp
\fBNOTE:\fP
.INDENT 0.0
.INDENT 3.5
The \fBOLD\fP behavior of a policy is
\fI\%deprecated by definition\fP
and may be removed in a future version of CMake.
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.UNINDENT
.SH COPYRIGHT
2000-2024 Kitware, Inc. and Contributors
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