CMake: Conditionally define symbols based on target platform?

[Ron Menelli]

I'm new to CMake after using QMake for many years. I mostly have my project working, but I can't find how to conditionally define symbols based on the platform I'm building for. In QMake, I could just do something like this:

macx: DEFINES += MAC_ONLY_SYMBOL

What's the equivalent in CMake?

[Christian Ehrlicher]

You should read about target_compile_definitions() to add a compile definition to your target and conditions to check for APPLE.

[Ron Menelli]

Thanks very much! The other piece I was missing is that CMake uses if/else statements. So, the result is:

if(APPLE)
    target_compile_options(mytarget PRIVATE -DMAC_ONLY_SYMBOL)
else()
    target_compile_options(mytarget PRIVATE -DOTHER_SYMBOL)
endif()