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copied!<p>The best way to specify sourcefiles in CMake is by <strong>listing them explicitly</strong>.</p> <p>The creators of CMake themselves advise <strong>not</strong> to use globbing.</p> <p>See: <a href="http://www.cmake.org/cmake/help/v3.3/command/file.html?highlight=glob#file" rel="noreferrer">http://www.cmake.org/cmake/help/v3.3/command/file.html?highlight=glob#file</a></p> <blockquote> <p>(We do not recommend using GLOB to collect a list of source files from your source tree. If no CMakeLists.txt file changes when a source is added or removed then the generated build system cannot know when to ask CMake to regenerate.)</p> </blockquote> <p>Of course, you might want to know what the downsides are - <em>read on!</em></p> <hr> <h2>When Globbing Fails:</h2> <p>The big disadvantage to globbing is that creating/deleting files won't automatically update the build-system.</p> <p>If you are the person adding the files, this may seem an acceptable trade-off, however this causes problems for other people building your code, they update the project from version-control, run build, then contact you, complaining that<br><strong>"the build's broken".</strong></p> <p>To make matters worse, the failure typically gives some linking error which doesn't give any hints to the cause of the problem and time is lost troubleshooting it.</p> <p><em>In a project I worked on we started off globbing but got so many complaints when new files were added, that it was enough reason to explicitly list files instead of globbing.</em></p> <p>This also breaks common git work-flows<br>(<code>git bisect</code> and switching between feature branches).</p> <p>So I couldn't recommend this, the problems it causes far outweigh the convenience, when someone can't build your software because of this, they may loose a lot of time to track down the issue or just give up.</p> <p>And another note, Just remembering to touch <code>CMakeLists.txt</code> isn't always enough, with automated builds that use globbing, I had to run <code>cmake</code> before <strong>every build</strong> since files <em>might</em> have been added/removed since last building *.</p> <h2>Exceptions to the rule:</h2> <p>There are times where globbing is preferable:</p> <ul> <li>For setting up a <code>CMakeLists.txt</code> files for existing projects that don't use CMake.<br>Its a fast way to get all the source referenced (once the build system's running - replace globbing with explicit file-lists).</li> <li>When CMake isn't used as the <strong>primary</strong> build-system, if for example you're using a project who aren't using CMake, and you would like to maintain your own build-system for it.</li> <li>For any situation where the file list changes so often that it becomes impractical to maintain. In this case it <em>could</em> be useful, but then you have to accept running <code>cmake</code> to generate build-files <em>every time</em> to get a reliable/correct build <em>(which goes against the intention of CMake - the ability to split configuration from building)</em>.</li> </ul> <hr> <p>* <em>Yes, I could have written a code to compare the tree of files on disk before and after an update, but this is not such a nice workaround and something better left up to the build-system.</em></p>

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