[c++] CMake does not find Visual C++ compiler

After installing Visual Studio 2015 and running CMake on a previous project, CMake errors stating that it could not find the C compiler.

The C compiler identification is unknown
The CXX compiler identification is unknown
CMake Error at CMakeLists.txt:4 (PROJECT):
  No CMAKE_C_COMPILER could be found.

CMake Error at CMakeLists.txt:4 (PROJECT):
  No CMAKE_CXX_COMPILER could be found.

I went searching for cl.exe in the Visual Studio folder,C:\Program Files\Microsoft Visual Studio 14.0, and could not find it.

How do I set up CMake to work on Windows with Visual Studio 2015?

Checking CMakeErrors.log in CMakeFiles returned:

C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V140\Platforms\x64\PlatformToolsets\v140_xp\Toolset.targets(36,5): warning MSB8003: Could not find WindowsSdkDir_71A variable from the registry. TargetFrameworkVersion or PlatformToolset may be set to an invalid version number.

The error means that the build tools for XP (v140_xp) are not installed. To fix it I installed the proper feature in Visual Studio 2019 installer under Individual Components tab:

I had a similar problem with the Visual Studio 2017 project generated through CMake. Some of the packages were missing while installing Visual Studio in Desktop development with C++. See snapshot:

Visual Studio 2017 Packages:

Also, upgrade CMake to the latest version.

I had this issue under Windows 10 when using Visual Studio 2015 Professional, while Visual Studio 2015 Express worked! Under Windows 7, both Visual Studio versions used to work.

New projects created from the Visual Studio 2015 Professional IDE successfully compile, but CMake would fail to find the compiler reporting:

The C compiler identification is unknown
The CXX compiler identification is unknown

I upgraded CMake from 3.4.1 to 3.11.4, and now the problem is gone.

Here is the solution that worked for me:

1. Open Visual Studio command prompt tool (as an administrator). On windows 10 it might be called 'Developer command prompt'.
2. Navigate to where you have the CMake executable
3. Run Cmake.exe
4. Proceed as usual to select build and source folder
5. Select the appropriate Visual Studio compiler and hit the configure button

Hopefully it should run without problems.

I ran into the same issue and fixed it by relaunching the Visual Studio Install and checking the following option:

Windows and Web Development / Universal Windows App Development Tools / Windows 10 SDK

It contains the standard C++ headers used in most applications and therefore it is often necessary to install it as well.

I looked in CMakeError.log file and found an error about cannot run 'rc.exe'

I searched and found this answer to copy RC.Exe and RcDll.Dll from the Microsoft SDKs bin to the VC bin, and then CMake worked.

Edit: The top answer to another question suggests that it's a PATH issue, so it could be enough to ensure the Microsoft SDK bin is in your PATH.

For me, I checked the CMakeError.log file and found:

[...] error MSB8036: The Windows SDK version 8.1 was not found. Install the required version of Windows SDK or change the SDK version in the project property pages or by right-clicking the solution and selecting "Retarget solution".

This is despite using Visual Studio 2017 on Windows 7. So it appears that CMake is trying to build its detection project with the Windows 8.1 SDK.

I used the Visual Studio installer to add that component and now CMake is happy as a clam.

I got this problem with CMake 3.12.1, after an update of Visual Studio 2017. I simply re-ran CMake and it worked.

Check name folder too long or not.

Because CMake is not able to find your Visual Studio compiler. Start any project which will download the required compilers and CMake must be able to find it then.

Those stumbling with this on Visual Studio 2017: there is a feature related to CMake that needs to be selected and installed together with the relevant compiler toolsets. See the screenshot below.

Make sure you are using the correct version of Visual Studio in the generator. I had incorrectly selected Visual Studio 15 when Visual Studio 14 installed.

In my case the issue was that the parent project, which is including googletest via

add_subdirectory(gtest_dir)

was defined as

PROJECT( projname CXX )

Somehow, CMake does not recognize

PROJECT(sub_project_name CXX C)

since the C compiler is not set in the parent.

I solved the issue by using

PROJECT( projname CXX C)

in my main CMakeLists.txt file.

In my case I could see in the CMakeError.log that CMake could not find the Windows SDK (MSB8003: Could not find WindowsSDKDir variable from the registry).

The version can be specified on the commandline on the first CMake run using:

-DCMAKE_VS_WINDOWS_TARGET_PLATFORM_VERSION=

I got further after setting that, but I hit more issues later (so I assume my environment is messed up somehow), but maybe it will help someone with this issue.

In my case there was an environment variable set which was the reason for this error. The problem was solved after deleting cxx_flags from the environment variables.

None of the previous solutions worked for me. However I noticed that although I installed Visual Studio version 15 (not to be confused with Visual Studio 2015) the directory created on my computer was for Visual Studio 14.

When I specified Visual Studio 14 when I pressed the configuration button it worked.

This might be another solution for those with the latest Windows 10 creator version:

Stack Overflow post Fatal error LNK1104: cannot open file 'gdi32.lib'

A couple of tips:

• Try to set the path manually by checking 'advanced' and modifying CMAKE_LINKER and CMAKE_MAKE_PROGRAM
• Delete the cache - in the CMake with GUI go to: File ? Delete Cache.

My problem was a combination of previously stated: I have set the compiler version to 15 instead of 14 and when corrected, I had to delete the cache.

I also started the Visual Studio command prompt as an administrator and from there I ran the cmake-gui.exe

Then everything worked as it was supposed to.

Resolved by adding the missing component Modify->continue add as follow

If you are on Visual Studio 2017 you need at least CMake 3.8!

I had a related problem: the Visual C++ generators were not even on the list when running cmake --help.

I ran where cmake in console and found that cygwin also provides its own cmake.exe file, which was being used. Changing the order of directories in PATH fixed the problem.

Look in the Cmakelists.txt if you find ARM you need to install C++ for ARM and as well vcvarsall.bat use for ARM bin folder.

It's these packages:

C++ Universal Windows Platform for ARM64 "Not Required"

Visual C++ Compilers and libraries for ARM "Not Required"

Visual C++ Compilers and libraries for ARM64 "Very Likely Required"

Required for finding Threads on ARM 
enable_language(C) 
enable_language(CXX)

Then the problems might disappear:

No CMAKE_C_COMPILER could be found.

No CMAKE_CXX_COMPILER could be found.

If above does not resolve your problem?

Optionally you can remove the options C and CXX in cmakelists.txt by setting # infront of where the enable_language(C) is. And avoid Android ARM processor compilation.

I had this issue with CMake GUI and the VS 21019 Community Edition. I think I may have installed CMake before Visual Studio - certainly after I updated CMake 3.15.2 to 3.15.3 the problem went away.

i found this sollution at stackoverflow and i work for me although not working other sollutions if you have a windows 10 OS, doing the following steps will fix the problem:

1) go to C:\Program Files (x86)\Microsoft SDKs\Windows\v7.1A\Bin

2) then copy RC.exe and RcDll from this file

3) go to C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin and paste the two files you have copied into it.

thats all i hope it is helpful...

If none of the above solutions worked, then stop and do a sanity check.

I got burned using the wrong -G <config> string and it gave me this misleading error.

First, run from the VS Command Prompt not the regular command prompt. You can find it in Start Menu -> Visual Studio 2015 -> MSBuild Command Prompt for VS2015 This sets up all the correct paths to VS tools, etc.

Now see what generators are available from cmake...

cmake -help

...<snip>... The following generators are available on this platform: Visual Studio 15 [arch] = Generates Visual Studio 15 project files. Optional [arch] can be "Win64" or "ARM". Visual Studio 14 2015 [arch] = Generates Visual Studio 2015 project files. Optional [arch] can be "Win64" or "ARM". Visual Studio 12 2013 [arch] = Generates Visual Studio 2013 project files. Optional [arch] can be "Win64" or "ARM". Visual Studio 11 2012 [arch] = Generates Visual Studio 2012 project files. Optional [arch] can be "Win64" or "ARM". Visual Studio 10 2010 [arch] = Generates Visual Studio 2010 project files. Optional [arch] can be "Win64" or "IA64". ...

Then chose the appropriate string with the [arch] added.

mkdir _build cd _build cmake .. -G "Visual Studio 15 Win64"

Running cmake in a subdirectory makes it easier to do a 'clean' since you can just delete everything in that directory.

I upgraded to Visual Studio 15 but wasn't paying attention and was trying to generate for 2012.

Menu ? Visual Studio 2015 ? MSBuild Command Prompt for Visual Studio 2015. Then CMake can find cl.exe.

set PATH="c:\Program Files (x86)\Windows Kits\10\bin\10.0.16299.0\x64\";%PATH%

Change the upper path to where your Windows SDK is installed.

CMake can find rc.exe.

cd to the path of CMakeLists.txt and do:

md .build
cd .build
cmake .. -G "Visual Studio 14 2015 Win64" -DCMAKE_BUILD_TYPE=Release
cmake --build .

The param after -G should be fetched by CMake. Use --help; you may or may not have the generator.