CMake on Windows

Because CMake’s error message is misleading here, I think it warrants a little more detailed answer.

In short, you ran into a chicken-and-egg kind of a problem.

CMake’s compiler detection is mighty, but since – during the first try –

• you didn’t give any explicit generator to use with -G
• it couldn’t find a Visual Studio installed
• it couldn’t find any C/C++ compiler in your PATH environment
• it couldn’t find a CC environment variable defined with the full path to a compiler

It was defaulting to nmake.

Now here comes the problem: it does remember your implicit generator/compiler choice in it’s variable cache (see CMAKE_GENERATOR in CMakeCache.txt). What is a very useful feature, if you have multiple compilers installed.

But if you then declare the CC environment variable – as the error message suggests – it’s too late since your generator’s choice was remembered in the first try.

I see two possible ways out of this:

1. Overrule the generator choice by given the right one with cmake.exe -G "MinGW Makefiles" .. (as the answer linked by @Guillaume suggests)
2. Delete your project’s binary output directory (including CMakeCache.txt) and do cmake.exe .. after you added your compiler’s bin folder to your PATH environment.

References

• Running CMake on Windows
• What is the default generator for CMake in Windows?
• CMake error at CMakeLists.txt:30 (project): No CMAKE_C_COMPILER could be found
• CMake: how to specify the version of Visual C++ to work with?