Question

In project with many multiple targets, I wish to add include libraries for a certain target only. I don’t want to slow down compilation by adding many include libraries to all projects, and I do want that if I did not specify a required library as a dependency to the executable, it will fail in compile time, and not only in link time.

Is there any way to do that in CMake? Something like target_link_libraries, but only for include directories?

Answer 1

First of all, I would not bother with a potential increase in compilation time, because you added many include-directories. Of course, you should test if it really is an issue.

You may try to specify the COMPILE_FLAGS property directly on the source files, but this is likely not cross-platform and needs to be done on each source-file.

Alternatively, consider splitting up your project in subdirectories and write a separate CMakeLists.txt for each subdir. In that case, the include_directories() call is limited to the scope of the current project (and its subprojects) and you would have more fine-grained control over each project.

There may be an issue with requiring failure at compilation time: E.g. when using static libraries A, depending on B, depending on C: When someones links an exe/dll to A, the libs B and C are needed, but this is not necessarily detectable at compile-time… and difficult to solve generically with CMake.