target_compile_definitions for multiple CMake targets?

Question

I've been told it's bad practice to do things like seting CFLAGS directly in CMake, and that, instead, I should use the target_compile_definitions() command.

Ok, but - what if I want to use similar/identical definitions for multiple (independent) targets? I don't want to repeat myself over and over again.

Answer 1

I see three possible ways:

1. The preferred one using target_compile_definitions(... INTERFACE/PUBLIC ...) which would self-propagate the compiler definitions to targets depending on it via target_link_libraries() command.

2. Using the set_property(TARGET target1 target2 ... APPEND PROPERTY COMPILE_DEFINITIONS ...) to set the same definitions to multiple targets.

3. You may still use the "old commands" of add_definitions() and remove_definitions() to modify COMPILE_DEFINITIONS directory property (which would pre-set all COMPILE_DEFINITIONS target properties in this directories scope).

References

• Is Cmake set variable recursive?
• CMake: Is there a difference between set_property(TARGET ...) and set_target_properties?