If project define string difinition or have debug compiller options - not work precompile header.

[talshadow]

if some in CMakeLists.txt have :
target_compile_definitions(test-cxx-force PUBLIC OPENFLAG="Open")
build wrong gch file.
if call cmake with -DCMAKE_BUILD_TYPE=Debug
build wrong gch file.
Try this lifehack :)

#export_all_flags("${_pch_flags_file}")
#set(_compiler_FLAGS "@${_pch_flags_file}")
add_custom_command(
OUTPUT "${_pchfile}"
COMMAND "${CMAKE_COMMAND}" -E copy "${_pch_header}" "${_pchfile}"
DEPENDS "${_pch_header}"
COMMENT "Updating ${_name}")
add_custom_command(
OUTPUT "${_output_cxx}"
COMMAND "${CMAKE_CXX_COMPILER}" $(CXX_DEFINES) $(CXX_FLAGS) -x c++-header -o "${_output_cxx}" "${_pchfile}"
DEPENDS "${_pchfile}" "${_pch_flags_file}"
COMMENT "Precompiling ${_name} for ${_target} (C++)")
add_custom_command(
OUTPUT "${_output_c}"
COMMAND "${CMAKE_C_COMPILER}" $(C_DEFINES) $(C_FLAGS) -x c-header -o "${_output_c}" "${_pchfile}"
DEPENDS "${_pchfile}" "${_pch_flags_file}"
COMMENT "Precompiling ${_name} for ${_target} (C)")

[wolfv]

I have a similar problem when trying to use C++11.
I defined using C++11 with set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
but it isn't picked up by this the precompiled header.

[phobos2077]

I have similar issue. I'm using set(CMAKE_CXX_STANDARD 14) but it doesn't got picked up by this script when compiling the header, and so compilation fails.

[bubnikv]

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

will not work. You have to use
add_compile_options(-std=c++11)
instead