cmake and clang++ windows build instead of MSVC - cmake

Question

I am trying to create a build environment using cmake and i have both MSVC and clang installed on my system.
When I run cmake with the default settings it detectts MSVC as my cxx compiler.
However, I would like to use clang++ instead.
I tried specifying clang like this: cmake -DCMAKE_CXX_COMPILER=clang++
but even after that it still uses MSVC..
How can I tell it to use clang instead?

Answer 1

You should provide the complete path of the clang compiler. E.g.,
cmake -DCMAKE_CXX_COMPILER=/path/to/clang++ -DCMAKE_C_COMPILER=/path/to/clang

Answer 2

First of all you need to ensure that CLANG is visible through a regular command prompt window. If not then you need to put the CLANG installed directory path to your PATH environment variable.
In my case I had clang-cl installed through Visual Studio but it was still not visible through a regular command prompt window.
Regular command prompt window output:
>clang-cl -v
'clang++' is not recognized as an internal or external command,
operable program or batch file.
Developer command prompt window output:
>clang-cl -v
clang version 12.0.0
Target: i686-pc-windows-msvc
Thread model: posix
InstalledDir: C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\Llvm\bin
Moreover, I simply use the following command: cmake -T ClangCL to generate the project on a Windows 10 PC with Visual Studio 2019 Professional Edition.
This is the output I get:
-- Building for: Visual Studio 16 2019
-- Selecting Windows SDK version 10.0.19041.0 to target Windows 10.0.19042.
-- The C compiler identification is Clang 12.0.0 with MSVC-like command-line
-- The CXX compiler identification is Clang 12.0.0 with MSVC-like command-line
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Professional/VC/Tools/Llvm/x64/bin/clang-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: C:/Program Files (x86)/Microsoft Visual Studio/2019/Professional/VC/Tools/Llvm/x64/bin/clang-cl.exe - skipped
I have tested the same on another Windows 10 PC with Visual Studio 2022 Community Edition and it works fine too.