licensing
GPL License guide
<p>I have read many articles about GPL because many libraries are using it and I use some of them inside a personal application I made.</p>

<p>After testing my application I am thinking of making it public.
It`s free of charge (freeware) and the problem is that I use a library as an external executable that is run by my application.  This external executable is on GPL license but my application is not (and does not use any GPL-licensed library within it).</p>

<p>Here are some links I read about the GPL license :</p>

<p><a href="https://noordering.wordpress.com/2009/01/20/why-the-gpl-is-not-free/" rel="nofollow noreferrer">Why the gpl is not free</a></p>

<p><a href="http://lucumr.pocoo.org/2009/2/12/are-you-sure-you-want-to-use-gpl/" rel="nofollow noreferrer">Are you sure you want to use GPL</a></p>

<p><a href="https://gist.github.com/LibCoder/4997f5d9954c63f6a3ca8920e91e4086" rel="nofollow noreferrer">Why not to use GPL and any GPL type license !</a></p>

<p>I do understand that anyone who uses a lib under GPL has to make his application open source, but I don`t know if I have to make just the executable that is under GPL license open source or if I have to make my application (which is not under the GPL licence) open source too?</p>

<p>Also I read that if an application is under GPL license you can`t use your own license and terms and conditions. Does this apply only to the GPL exe? or also to my exe which is not GPL?</p>

<p>The core misunderstanding you have is hinted at by the question in your last paragraph.</p>

<p>Forget "open source", there are (sadly) many hundred open source licences.  The GPL requires that any "derivative work" of GPL licensed code must <em>also</em> be licensed under the GPL <em>if it is distributed</em>.</p>

<p>So the question is, does an application which runs an executable created from GPL licensed code constitute "a derivative work"?  I am not a lawyer (and in particular, I am not an intellectual property lawyer), but I don't think it does.  Therefore you can distribute the GPL'ed executable, and your own application without having to license your application under the GPL.</p>

<p>If you make any modifications to the GPL'ed library to support your application, you must GPL those modifications, and hence you must distribute the source to those modifications (a link to Github would probably be sufficient).</p>
