CMake/MinGW unknown compilers, gcc.exe broken - c++

Question

I am trying to install on my windows desktop, a software suite called NUPACK which is used to design nucleic acid reaction pathways. http://www.nupack.org/
This software requires CMake to install, and from my understanding, CMake does not have compilers by itself, and requires us to have compilers separately installed. As such, I downloaded MinGW to use as a C++ compiler. Prior to running, I have set the environment variables of both CMake and MinGW's bin. I am running CMake (version 3.11.1) through the command prompt but I keep encountering the following problem:
C:\Users\Nicholas\Documents\nupack\build>Cmake -DCMAKE_INSTALL_PREFIX=NUPACKINSTALL -G "MinGW Makefiles" ..
-- The C compiler identification is unknown
-- The CXX compiler identification is unknown
-- Check for working C compiler: C:/MinGW/bin/gcc.exe
-- Check for working C compiler: C:/MinGW/bin/gcc.exe -- broken
CMake Error at C:/Program Files/CMake/share/cmake-
3.11/Modules/CMakeTestCCompiler.cmake:52 (message):
The C compiler
"C:/MinGW/bin/gcc.exe"
is not able to compile a simple test program.
I'm guessing CMake cannot identify my MinGW gcc and gcc++ compilers somehow. I tried the following next, but the same error arose.
set CMAKE_C_COMPILER=%C:\mingw\bin\gcc%
set CMAKE_CXX_COMPILER=%C:\mingw\bin\g++%
Has anyone encountered the same problem? Can this be resolved by using MinGW64? I am using Windows 10 and previously, I tried using visual studio 2017's compilers, but it had its on set of problems too.

Answer 1

Yes, the problem is that CMake cannot find GCC compiler. Before be sure that g++ and gcc are installed. It can be MinGW64 or Cygwin.
There are at least three ways to link GCC compiler.
1st way:
Set compilers in CMakeLists.txt:
set(CMAKE_C_COMPILER C:\path\to\gcc.exe)
set(CMAKE_CXX_COMPILER C:\path\to\g++.exe)
2nd way:
When calling cmake in terminal or cmd:
cmake -DCMAKE_C_COMPILER="C:\path\to\gcc.exe" -DCMAKE_CXX_COMPILER="C:\path\to\g++.exe"
3rd way:
Set as environment variable:
Go to Windows "Environment Variables" and add to PATH this:
;C:\path_to_MinGW_or_Cygwin\bin

Answer 2

I had similar problem.
My Setup was : VSCode (Windows 10) + GCC 9.2xx + CMake 3.18.2
Environment variables were already set to point to GCC and CMake.
This Worked: https://stackoverflow.com/a/4101496/2865353
Needs to cleanup CMakeCache.txt and CMakeFiles directory.
Erros it fixed are:
-- Building for: NMake Makefiles
-- The C compiler identification is unknown
-- The CXX compiler identification is unknown
CMake Error at CMakeLists.txt:3 (project):
The CMAKE_C_COMPILER:
cl
is not a full path and was not found in the PATH.
CMake Error at CMakeLists.txt:3 (project):
The CMAKE_CXX_COMPILER:
cl
is not a full path and was not found in the PATH.