CMake: how to select a different shell - c++

Question

Using CMake, how to choose the shell to be used? Mine seems to be set to sh by default, but I need some environment vars loaded from my .bashrc, and I guess changing the shell is the way to go.
I'm actually trying to set clang++ as the C++ compiler, with the following directive:
set (CMAKE_CXX_COMPILER "clang++")
But when I try to compile the code, the shell being used is sh, and it does not find clang++, as I make the binary visible via the following export, in my .bashrc:
export PATH="${PATH}:~/llvm/Debug+Asserts/bin/"
Here is the error, confirming sh cannot find the clang++ binary:
$ make
[100%] Building CXX object CMakeFiles/floyd-warshall.dir/main.cpp.o
/bin/sh: 1: clang++: not found
make[2]: *** [CMakeFiles/floyd-warshall.dir/main.cpp.o] Error 127
make[1]: *** [CMakeFiles/floyd-warshall.dir/all] Error 2
make: *** [all] Error 2

Answer 1

You should not force the c++ compiler this way in your cmake file (at first I thought you were using a toolchain file). Remove that line and let CMake finds the compiler by itself. To use clang++ set some environment variables before calling cmake. Something like:
export CC=clang
export CXX=clang++
cmake /path/to/your/project
make