1# - Compile and run code to check for C++ features
2#
3# This functions compiles a source file under the `cmake` folder
4# and adds the corresponding `HAVE_[FILENAME]` flag to the CMake
5# environment
6#
7#  cxx_feature_check(<FLAG> [<VARIANT>])
8#
9# - Example
10#
11# include(CXXFeatureCheck)
12# cxx_feature_check(STD_REGEX)
13# Requires CMake 2.6+
14
15if(__cxx_feature_check)
16  return()
17endif()
18set(__cxx_feature_check INCLUDED)
19
20function(cxx_feature_check FILE)
21  string(TOLOWER ${FILE} FILE)
22  string(TOUPPER ${FILE} VAR)
23  string(TOUPPER "HAVE_${VAR}" FEATURE)
24  message("-- Performing Test ${FEATURE}")
25  try_run(RUN_${FEATURE} COMPILE_${FEATURE}
26          ${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/cmake/${FILE}.cpp)
27  if(RUN_${FEATURE} EQUAL 0)
28    message("-- Performing Test ${FEATURE} -- success")
29    set(HAVE_${VAR} 1 PARENT_SCOPE)
30    add_definitions(-DHAVE_${VAR})
31  else()
32    if(NOT COMPILE_${FEATURE})
33      message("-- Performing Test ${FEATURE} -- failed to compile")
34    else()
35      message("-- Performing Test ${FEATURE} -- compiled but failed to run")
36    endif()
37  endif()
38endfunction()
39
40