Windows configure error when using the command line: "The C/CXX compiler identification is unknown.."

Usage
1

I fail to use the command line to configure, reporting errors as “The C compiler identification is unknown and The CXX compiler identification is unknown”.
image

But for the same project, it is successful when using the cmake-gui. My cmake version is 3.20.4.
report information like:
Selecting Windows SDK version 10.0.19041.0 to target Windows 10.0.19042.
The C compiler identification is MSVC 19.16.27045.0
The CXX compiler identification is MSVC 19.16.27045.0
Detecting C compiler ABI info
Detecting C compiler ABI info - done
Check for working C compiler: D:/Program Files/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x86/cl.exe - skipped
Detecting C compile features
Detecting C compile features - done
Detecting CXX compiler ABI info
Detecting CXX compiler ABI info - done
Check for working CXX compiler: D:/Program Files/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x86/cl.exe - skipped
Detecting CXX compile features
Detecting CXX compile features - done
operation system is Windows-10.0.19042
Found OpenMP_C: -openmp (found version “2.0”)
Found OpenMP_CXX: -openmp (found version “2.0”)
Found OpenMP: TRUE (found version “2.0”)

Anyone could help? I don’t know why there is a difference in my vs2017 build and how to solve it in command-line way.

2

Guessing: The cmake-gui chooses the 32bit (host and target) version of the compiler. You choose the host=64bit version with CLI

3

When you use the GUI it appears to be using the Hostx86 tools not Hostx64. Did the command line version work when not specifying the toolset with -T.

4

It still has the same prompt error when removing the “-T” option.

5

I try to add the x86 compiler path “D:\Program Files\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.16.27023\bin\Hostx86\x86” to the system environment path, it still has the same error.

Actually, I don’t know how the cmake-gui works and why it chooses the x86/32bits option. And how it detects the complier information of:

The C compiler identification is MSVC 19.16.27045.0
The CXX compiler identification is MSVC 19.16.27045.0

I have local search results for the cl.exe as shown below…

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image860×252 131 KB

6

Usually this means that something like the SDK isn’t installed. Does the toolchain work outside of CMake?

7

I tested a simple cpp file using the shell of MSVC tool, the cl build was successful.

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image873×398 18.7 KB

While I try the cmake command in the same shell, it prompt the same error…
– Selecting Windows SDK version 10.0.19041.0 to target Windows 10.0.19042.
– The C compiler identification is unknown
– The CXX compiler identification is unknown
CMake Error at CMakeLists.txt:2 (project):
No CMAKE_C_COMPILER could be found.
CMake Error at CMakeLists.txt:2 (project):
No CMAKE_CXX_COMPILER could be found.

8

Hello @StevenWang we ended up finding a solution over on this discourse. Try temporarily minimizing your PATH variable to see if that helps as shown in that thread.

9

Yes, minimizing the PATH in temp can solve this CLI issue!

Thank you and everyone who helped me so much.