include(CheckCXXSymbolExists)

# - Check if the symbol exists in include files, in C++ mode

# Forked off cmake's CheckSymbolExists.cmake

# CHECK_CXX_SYMBOL_EXISTS(SYMBOL FILES VARIABLE)

#

#  SYMBOL   - symbol

#  FILES    - include files to check

#  VARIABLE - variable to return result

#

# The following variables may be set before calling this macro to

# modify the way the check is run:

#

#  CMAKE_REQUIRED_FLAGS = string of compile command line flags

#  CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)

#  CMAKE_REQUIRED_INCLUDES = list of include directories

#  CMAKE_REQUIRED_LIBRARIES = list of libraries to link

MACRO(CHECK_CXX_SYMBOL_EXISTS SYMBOL FILES VARIABLE)

  IF("${VARIABLE}" MATCHES "^${VARIABLE}$")

    SET(CMAKE_CONFIGURABLE_FILE_CONTENT "/* */\n")

    SET(MACRO_CHECK_SYMBOL_EXISTS_FLAGS ${CMAKE_REQUIRED_FLAGS})

    IF(CMAKE_REQUIRED_LIBRARIES)

      SET(CHECK_SYMBOL_EXISTS_LIBS 

        "-DLINK_LIBRARIES:STRING=${CMAKE_REQUIRED_LIBRARIES}")

    ELSE(CMAKE_REQUIRED_LIBRARIES)

      SET(CHECK_SYMBOL_EXISTS_LIBS)

    ENDIF(CMAKE_REQUIRED_LIBRARIES)

    IF(CMAKE_REQUIRED_INCLUDES)

      SET(CMAKE_SYMBOL_EXISTS_INCLUDES

        "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")

    ELSE(CMAKE_REQUIRED_INCLUDES)

      SET(CMAKE_SYMBOL_EXISTS_INCLUDES)

    ENDIF(CMAKE_REQUIRED_INCLUDES)

    FOREACH(FILE ${FILES})

      SET(CMAKE_CONFIGURABLE_FILE_CONTENT

        "${CMAKE_CONFIGURABLE_FILE_CONTENT}#include <${FILE}>\n")

    ENDFOREACH(FILE)

    SET(CMAKE_CONFIGURABLE_FILE_CONTENT

      "${CMAKE_CONFIGURABLE_FILE_CONTENT}\nvoid cmakeRequireSymbol(int dummy,...){(void)dummy;}\nint main()\n{\n#ifndef ${SYMBOL}\n  cmakeRequireSymbol(0,&${SYMBOL});\n#endif\n  return 0;\n}\n")

    CONFIGURE_FILE("${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in"

      "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx" @ONLY)

    MESSAGE(STATUS "Looking for ${SYMBOL}")

    TRY_COMPILE(${VARIABLE}

      ${CMAKE_BINARY_DIR}

      ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx

      COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}

      CMAKE_FLAGS 

      -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_SYMBOL_EXISTS_FLAGS}

      "${CHECK_SYMBOL_EXISTS_LIBS}"

      "${CMAKE_SYMBOL_EXISTS_INCLUDES}"

      OUTPUT_VARIABLE OUTPUT)

    IF(${VARIABLE})

      MESSAGE(STATUS "Looking for ${SYMBOL} - found")

      SET(${VARIABLE} 1 CACHE INTERNAL "Have symbol ${SYMBOL}")

      FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log 

        "Determining if the ${SYMBOL} "

        "exist passed with the following output:\n"

        "${OUTPUT}\nFile ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx:\n"

        "${CMAKE_CONFIGURABLE_FILE_CONTENT}\n")

    ELSE(${VARIABLE})

      MESSAGE(STATUS "Looking for ${SYMBOL} - not found.")

      SET(${VARIABLE} "" CACHE INTERNAL "Have symbol ${SYMBOL}")

      FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log 

        "Determining if the ${SYMBOL} "

        "exist failed with the following output:\n"

        "${OUTPUT}\nFile ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx:\n"

        "${CMAKE_CONFIGURABLE_FILE_CONTENT}\n")

    ENDIF(${VARIABLE})

  ENDIF("${VARIABLE}" MATCHES "^${VARIABLE}$")

ENDMACRO(CHECK_CXX_SYMBOL_EXISTS)