| # - Compile and run code to check for C++ features |
| # |
| # This functions compiles a source file under the `cmake` folder |
| # and adds the corresponding `HAVE_[FILENAME]` flag to the CMake |
| # environment |
| # |
| # cxx_feature_check(<FLAG> [<VARIANT>]) |
| # |
| # - Example |
| # |
| # include(CXXFeatureCheck) |
| # cxx_feature_check(STD_REGEX) |
| # Requires CMake 2.8.12+ |
| |
| if(__cxx_feature_check) |
| return() |
| endif() |
| set(__cxx_feature_check INCLUDED) |
| |
| function(cxx_feature_check FILE) |
| string(TOLOWER ${FILE} FILE) |
| string(TOUPPER ${FILE} VAR) |
| string(TOUPPER "HAVE_${VAR}" FEATURE) |
| if (DEFINED HAVE_${VAR}) |
| set(HAVE_${VAR} 1 PARENT_SCOPE) |
| add_definitions(-DHAVE_${VAR}) |
| return() |
| endif() |
| |
| if (NOT DEFINED COMPILE_${FEATURE}) |
| message(STATUS "Performing Test ${FEATURE}") |
| if(CMAKE_CROSSCOMPILING) |
| try_compile(COMPILE_${FEATURE} |
| ${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/cmake/${FILE}.cpp |
| CMAKE_FLAGS ${BENCHMARK_CXX_LINKER_FLAGS} |
| LINK_LIBRARIES ${BENCHMARK_CXX_LIBRARIES}) |
| if(COMPILE_${FEATURE}) |
| message(WARNING |
| "If you see build failures due to cross compilation, try setting HAVE_${VAR} to 0") |
| set(RUN_${FEATURE} 0 CACHE INTERNAL "") |
| else() |
| set(RUN_${FEATURE} 1 CACHE INTERNAL "") |
| endif() |
| else() |
| message(STATUS "Performing Test ${FEATURE}") |
| try_run(RUN_${FEATURE} COMPILE_${FEATURE} |
| ${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/cmake/${FILE}.cpp |
| CMAKE_FLAGS ${BENCHMARK_CXX_LINKER_FLAGS} |
| LINK_LIBRARIES ${BENCHMARK_CXX_LIBRARIES}) |
| endif() |
| endif() |
| |
| if(RUN_${FEATURE} EQUAL 0) |
| message(STATUS "Performing Test ${FEATURE} -- success") |
| set(HAVE_${VAR} 1 PARENT_SCOPE) |
| add_definitions(-DHAVE_${VAR}) |
| else() |
| if(NOT COMPILE_${FEATURE}) |
| message(STATUS "Performing Test ${FEATURE} -- failed to compile") |
| else() |
| message(STATUS "Performing Test ${FEATURE} -- compiled but failed to run") |
| endif() |
| endif() |
| endfunction() |
