基于CMake平台的Clang

Question

I'm setting up a cross platform build environment. For that reason I've chosen to go for clang, for the, correct me if I'm wrong reasons:

• Using the "same" compiler for different platform would potentially reduce the quirks that arise when getting gcc code to work with MSVC
• Clang with its MSVC compatible ABI would let me work with the WINAPI as if I were using MSVC.

My question is: How do I get CMake to, based on the platform, find the correct clang to use, that is clang-cl in Windows and clang on *nix platforms ?

Please note that I'll be using Ninja generator for CMake, and the project is Qt based, if that matters.

Answer 1

You (the project author) don't get to choose the compiler, the user that invokes CMake chooses the compiler.

The only thing you can do from within the CMakeLists is abort with an error if you are not happy with the choice that the user made.

There are a couple of ways how the user can specify to CMake which compiler to use. Popular examples include setting the respective environment variables , passing it via -DCMAKE_CXX_COMPILER on the first CMake run (and only on the first run; you cannot change this later without re-configuring from scratch!), or by using a toolchain file .

On Visual Studio, you can also use the -T option to select a build toolchain. This allows you to build with clang from Visual Studio.

You should document in your project's Readme which compiler you expect your users to configure for CMake and maybe give them a small example how to do this via one of the methods above.