Question: why add_library(project_warnings INTERFACE) is not inside cmake/CompilerWarnings.cmake?

[Vincas Dargis]

Sorry for maybe a silly and obvious question, but since I'm qmake user switching to cmake.. why is that it's not CompilerWarnings.cmake that defines that INTERFACE fake-library called project_warnings to be used in all targets you might need? CompilerWarnings.cmake would seem kinda more "complete" if it did by itself.

Or is there some sort of CMake limitation, or better flexibility to do that in two-step: helper .cmake has a function, but target created on the root CMakeLists.txt?

Thanks!

[Jason Turner]

@Talkless This is intentional to give finer grained control over which compiler warnings get applied to which sub projects.

For example - we don't want a noisy third-party library to cause a bunch of warnings. This way we link in the project_warnings in the projects we have (and we may have many sub projects, which is another reason we cannot do it automatically in CompilerWarnings.cmake, because we don't know all of the possible sub project names at this point.)