[CMake] Selecting compiler on Windows platform

[Josef Karthauser]

I’m a bit confused, as ever ☺.

I’ve got a number of windows compilers, cl and gcc for instance, and I want to specify which one I want to use.
I can do this using an environment variable thus,

    % env CXX=gcc cmake –G’NMake Makefiles’ .

which allows CMakeDetermineCXXCompiler.cmake to override the ‘cl’ default that the NMake generator sets.

However, I’d like to control this from within a CMake file, and this doesn’t appear possible.  From what I can see, CMakeDetermineCXXCompiler is loaded and executed prior to the CMakeLists.txt file, which means that I cannot set the compiler internally.  Is this true, or is there something I’m not aware of?

What I’d like to do is something like:

  CMakeLists.txt:
	IF(... some condition ...)
		SET(ENV{CXX} “gcc”)
	ELSE
		SET(ENV{CXX} “cl”)
	ENDIF(... some condition ...)

	... NORMAL BUILD RULES ...

 Should this be possible?  If not, I’ll have to wrap the contents of the CMakeLists file with a IF(INNERLOOP) and then call CMake –DINNERLOOP=1 from within the CMakeLists.txt file, after setting the environment variable, which is a bit gnarly.

Joe