c++ - How can I make CMake use GCC instead of Clang on Mac OS X?

Question

I can't find any info on it, but only the other way around (e.g., how to set CMake to use clang).

I've installed gcc-4.8 using brew, setup all dependencies, headers, etc, and now CMake refuses to use gcc.

I've set my bash profile with both aliases and actual entries:

export CC=/usr/bin/gcc
export CXX=/usr/bin/g++
alias gcc='gcc-4.8'
alias cc='gcc-4.8'
alias g++='g++-4.8'
alias c++='c++-4.8'

Yet CMake stubbornly refuses to use gcc and instead reverts back to clang:

air:build alex$ cmake -DCMAKE_BUILD_TYPE=DEBUG ..
-- The C compiler identification is Clang 5.1.0
-- The CXX compiler identification is Clang 5.1.0
-- Check for working C compiler: /usr/bin/gcc
-- Check for working C compiler: /usr/bin/gcc -- works

Answer 1

CMake doesn't (always) listen to CC and CXX. Instead use CMAKE_C_COMPILER and CMAKE_CXX_COMPILER:

cmake -DCMAKE_C_COMPILER=/usr/bin/gcc -DCMAKE_CXX_COMPILER=/usr/bin/g++ ...

See also the documentation.

Alternatively, you can provide a toolchain file, but that might be overkill in this case.