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--- |
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c: Copyright (C) Daniel Stenberg, <[email protected]>, et al. |
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SPDX-License-Identifier: curl |
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Title: curl_easy_send |
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Section: 3 |
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Source: libcurl |
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See-also: |
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- curl_easy_getinfo (3) |
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- curl_easy_perform (3) |
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- curl_easy_recv (3) |
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- curl_easy_setopt (3) |
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Protocol: |
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- All |
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Added-in: 7.18.2 |
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--- |
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# NAME |
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curl_easy_send - sends raw data over an "easy" connection |
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# SYNOPSIS |
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~~~c |
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#include <curl/curl.h> |
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CURLcode curl_easy_send(CURL *curl, const void *buffer, |
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size_t buflen, size_t *n); |
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~~~ |
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# DESCRIPTION |
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This function sends arbitrary data over the established connection. You may |
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use it together with curl_easy_recv(3) to implement custom protocols |
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using libcurl. This functionality can be particularly useful if you use |
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proxies and/or SSL encryption: libcurl takes care of proxy negotiation and |
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connection setup. |
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**buffer** is a pointer to the data of length **buflen** that you want |
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sent. The variable **n** points to receives the number of sent bytes. |
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To establish the connection, set CURLOPT_CONNECT_ONLY(3) option before |
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calling curl_easy_perform(3) or curl_multi_perform(3). Note that |
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curl_easy_send(3) does not work on connections that were created without |
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this option. |
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The call returns **CURLE_AGAIN** if it is not possible to send data right now |
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- the socket is used in non-blocking mode internally. When **CURLE_AGAIN** |
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is returned, use your operating system facilities like *select(2)* to wait |
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until the socket is writable. The socket may be obtained using |
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curl_easy_getinfo(3) with CURLINFO_ACTIVESOCKET(3). |
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Furthermore if you wait on the socket and it tells you it is writable, |
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curl_easy_send(3) may return **CURLE_AGAIN** if the only data that was sent |
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was for internal SSL processing, and no other data could be sent. |
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# %PROTOCOLS% |
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# EXAMPLE |
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~~~c |
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int main(void) |
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{ |
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CURL *curl = curl_easy_init(); |
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if(curl) { |
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CURLcode res; |
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com"); |
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/* Do not do the transfer - only connect to host */ |
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curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 1L); |
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res = curl_easy_perform(curl); |
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if(res == CURLE_OK) { |
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long sockfd; |
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size_t sent; |
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/* Extract the socket from the curl handle - we need it for waiting. */ |
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res = curl_easy_getinfo(curl, CURLINFO_ACTIVESOCKET, &sockfd); |
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/* send data */ |
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res = curl_easy_send(curl, "hello", 5, &sent); |
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} |
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} |
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} |
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~~~ |
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# %AVAILABILITY% |
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# RETURN VALUE |
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On success, returns **CURLE_OK** and stores the number of bytes actually |
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sent into ***n**. Note that this may be less than the amount you wanted to |
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send. |
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On failure, returns the appropriate error code. |
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This function may return **CURLE_AGAIN**. In this case, use your operating |
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system facilities to wait until the socket is writable, and retry. |
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If there is no socket available to use from the previous transfer, this function |
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returns **CURLE_UNSUPPORTED_PROTOCOL**. |
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