Using pre-compiled headers with CMake

Question

I have seen a few (old) posts on the \'net about hacking together some support for pre-compiled headers in CMake. They all seem a bit all-over the place and everyone has the

Answer 1

Im using the following macro to generate and use precompiled headers:

MACRO(ADD_MSVC_PRECOMPILED_HEADER PrecompiledHeader PrecompiledSource SourcesVar)
  IF(MSVC)
    GET_FILENAME_COMPONENT(PrecompiledBasename ${PrecompiledHeader} NAME_WE)
    SET(PrecompiledBinary "${CMAKE_CURRENT_BINARY_DIR}/${PrecompiledBasename}.pch")
    SET(Sources ${${SourcesVar}})

    SET_SOURCE_FILES_PROPERTIES(${PrecompiledSource}
                                PROPERTIES COMPILE_FLAGS "/Yc\"${PrecompiledHeader}\" /Fp\"${PrecompiledBinary}\""
                                           OBJECT_OUTPUTS "${PrecompiledBinary}")
    SET_SOURCE_FILES_PROPERTIES(${Sources}
                                PROPERTIES COMPILE_FLAGS "/Yu\"${PrecompiledHeader}\" /FI\"${PrecompiledHeader}\" /Fp\"${PrecompiledBinary}\""
                                           OBJECT_DEPENDS "${PrecompiledBinary}")  
    # Add precompiled header to SourcesVar
    LIST(APPEND ${SourcesVar} ${PrecompiledSource})
  ENDIF(MSVC)
ENDMACRO(ADD_MSVC_PRECOMPILED_HEADER)

Lets say you have a variable ${MySources} with all your sourcefiles, the code you would want to use would be simply be

ADD_MSVC_PRECOMPILED_HEADER("precompiled.h" "precompiled.cpp" MySources)
ADD_LIBRARY(MyLibrary ${MySources})

The code would still function just fine on non-MSVC platforms too. Pretty neat :)