cmake/CheckFunctionExistsEx.cmake

   1 # - Check if a C function can be linked
   2 # CHECK_FUNCTION_EXISTS(<function> <variable>)
   3 #
   4 # Check that the <function> is provided by libraries on the system and
   5 # store the result in a <variable>.  This does not verify that any
   6 # system header file declares the function, only that it can be found
   7 # at link time (considure using CheckSymbolExists).
   8 #
   9 # The following variables may be set before calling this macro to
  10 # modify the way the check is run:
  11 #
  12 #  CMAKE_REQUIRED_FLAGS = string of compile command line flags
  13 #  CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)
  14 #  CMAKE_REQUIRED_INCLUDES = list of include directories
  15 #  CMAKE_REQUIRED_LIBRARIES = list of libraries to link
  16
  17 #=============================================================================
  18 # Copyright 2002-2011 Kitware, Inc.
  19 #
  20 # Distributed under the OSI-approved BSD License (the "License");
  21 # see accompanying file Copyright.txt for details.
  22 #
  23 # This software is distributed WITHOUT ANY WARRANTY; without even the
  24 # implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  25 # See the License for more information.
  26 #=============================================================================
  27 # (To distribute this file outside of CMake, substitute the full
  28 #  License text for the above reference.)
  29
  30 MACRO(CHECK_FUNCTION_EXISTS_EX FUNCTION VARIABLE)
  31   IF("${VARIABLE}" MATCHES "^${VARIABLE}$")
  32     SET(MACRO_CHECK_FUNCTION_DEFINITIONS
  33       "-DCHECK_FUNCTION_EXISTS=${FUNCTION} ${CMAKE_REQUIRED_FLAGS}")
  34     MESSAGE(STATUS "Looking for ${FUNCTION}")
  35     IF(CMAKE_REQUIRED_LIBRARIES)
  36       SET(CHECK_FUNCTION_EXISTS_ADD_LIBRARIES
  37         "-DLINK_LIBRARIES:STRING=${CMAKE_REQUIRED_LIBRARIES}")
  38     ELSE(CMAKE_REQUIRED_LIBRARIES)
  39       SET(CHECK_FUNCTION_EXISTS_ADD_LIBRARIES)
  40     ENDIF(CMAKE_REQUIRED_LIBRARIES)
  41     IF(CMAKE_REQUIRED_INCLUDES)
  42       SET(CHECK_FUNCTION_EXISTS_ADD_INCLUDES
  43         "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
  44     ELSE(CMAKE_REQUIRED_INCLUDES)
  45       SET(CHECK_FUNCTION_EXISTS_ADD_INCLUDES)
  46     ENDIF(CMAKE_REQUIRED_INCLUDES)
  47     TRY_COMPILE(${VARIABLE}
  48       ${CMAKE_BINARY_DIR}
  49           ${PROJECT_SOURCE_DIR}/cmake/CheckFunctionExistsEx.c
  50       COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
  51       CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_FUNCTION_DEFINITIONS}
  52       "${CHECK_FUNCTION_EXISTS_ADD_LIBRARIES}"
  53       "${CHECK_FUNCTION_EXISTS_ADD_INCLUDES}"
  54       OUTPUT_VARIABLE OUTPUT)
  55     IF(${VARIABLE})
  56       SET(${VARIABLE} 1 CACHE INTERNAL "Have function ${FUNCTION}")
  57       MESSAGE(STATUS "Looking for ${FUNCTION} - found")
  58       FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
  59         "Determining if the function ${FUNCTION} exists passed with the following output:\n"
  60         "${OUTPUT}\n\n")
  61     ELSE(${VARIABLE})
  62       MESSAGE(STATUS "Looking for ${FUNCTION} - not found")
  63       SET(${VARIABLE} "" CACHE INTERNAL "Have function ${FUNCTION}")
  64       FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
  65         "Determining if the function ${FUNCTION} exists failed with the following output:\n"
  66         "${OUTPUT}\n\n")
  67     ENDIF(${VARIABLE})
  68   ENDIF("${VARIABLE}" MATCHES "^${VARIABLE}$")
  69 ENDMACRO(CHECK_FUNCTION_EXISTS_EX)