Setting the MSVC runtime in CMake

Question

I\'m following the instructions in the CMake FAQ entry \"How can I build my MSVC application with a static runtime?\" to centralize selection of the MSVC runtime for a bunch

Answer 1

Here is a solution that I came up with, which should work for CMake versions before and after 3.15.

# This logic needs to be considered before project()
set(_change_MSVC_flags FALSE)
if(WIN32)
  if(CMAKE_VERSION VERSION_LESS 3.15.0)
    set(_change_MSVC_flags TRUE)
  else()
    # Set MSVC runtime to MultiThreaded (/MT)
    cmake_policy(SET CMP0091 NEW)
    set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$:Debug>")
  endif()
endif()

project(MyProj ....)

if(_change_MSVC_flags)
  # Modify compile flags to change MSVC runtime from /MD to /MT
  set(_re_match "([\\/\\-]M)D")
  set(_re_replace "\\1T")
  string(REGEX REPLACE ${_re_match} ${_re_replace}
    CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
  string(REGEX REPLACE ${_re_match} ${_re_replace}
    CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
  string(REGEX REPLACE ${_re_match} ${_re_replace}
    CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}")
  string(REGEX REPLACE ${_re_match} ${_re_replace}
    CMAKE_CXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL}")
  string(REGEX REPLACE ${_re_match} ${_re_replace}
    CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
endif()

If other languages are used (i.e. C), then these would also need to be added too.