Cmake error setting compiler

Question

For some reason, CMake's C and C++ compilers are set by default to /usr/bin/qcc. I've followed this post and tried the command

cmake -D CMAKE_C_COMPILER=/usr/bin/gcc -D CMAKE_CXX_COMPILER=/usr/bin/g++

but I get the error

CMake Error: The source directory [current directory]/CMAKE_CXX_COMPILER=/usr/bin/g++" does not exist.

Why is CMake interpreting my commands as a directory, and what is the correct way to set CMake's compilers?

Answer 1

It's CMAKE_CXX_COMPILER, not C++.

Answer 2

You've got the right idea, however the command line you want is:

cmake -DCMAKE_C_COMPILER=/usr/bin/gcc -DCMAKE_CXX_COMPILER=/usr/bin/g++ <path_to_source>

The differences are subtle. There should be no space between the -D and the variable being set, which is why CMake is interpreting your variable assignment as a directory. Also CMake uses CXX for C++ specific variables, which keeps it consistent with Make.