#
# Check if the function exists.
#
# CHECK_FUNCTION_EXISTS - macro which checks if the function exists
# FUNCTION - the name of the function
# VARIABLE - variable to store the result
#

MACRO(CHECK_FUNCTION_EXISTS FUNCTION VARIABLE)
  SET(MACRO_CHECK_FUNCTION_DEFINITIONS -DCHECK_FUNCTION_EXISTS=${FUNCTION})
  MESSAGE(STATUS "Looking for ${FUNCTION}")
  TRY_COMPILE(${VARIABLE}
             ${PROJECT_BINARY_DIR}
             ${CMAKE_ROOT}/Modules/CheckFunctionExists.c
             CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_FUNCTION_DEFINITIONS}
             OUTPUT_VARIABLE OUTPUT)
  IF(${VARIABLE})
    SET(${VARIABLE} 1 CACHE INTERNAL "Have function ${FUNCTION}")
    MESSAGE(STATUS "Found ${FUNCTION}")
  ELSE(${VARIABLE})
    MESSAGE(STATUS "${FUNCTION} not found")
    SET(${VARIABLE} "" CACHE INTERNAL "Have function ${FUNCTION}")
    WRITE_FILE(${PROJECT_BINARY_DIR}/CMakeError.log 
      "Determining if the function ${FUNCTION} exists failed with the following output:\n"
      "${OUTPUT}\n" APPEND)
  ENDIF(${VARIABLE})
ENDMACRO(CHECK_FUNCTION_EXISTS)