CMake/Modules/CheckVariableExists.cmake

34 lines
1.4 KiB
CMake

#
# Check if the variable exists.
# # CHECK_VARIABLE_EXISTS - macro which checks if the variable exists
# VAR - the name of the variable
# VARIABLE - variable to store the result
#
MACRO(CHECK_VARIABLE_EXISTS VAR VARIABLE)
IF("${VARIABLE}" MATCHES "^${VARIABLE}$")
SET(MACRO_CHECK_VARIABLE_DEFINITIONS -DCHECK_VARIABLE_EXISTS=${VAR})
MESSAGE(STATUS "Looking for ${VARIABLE}")
IF(CMAKE_REQUIRED_LIBRARIES)
SET(CHECK_VARIABLE_EXISTS_ADD_LIBRARIES
"-DLINK_LIBRARIES:STRING=${CMAKE_REQUIRED_LIBRARIES}")
ENDIF(CMAKE_REQUIRED_LIBRARIES)
TRY_COMPILE(${VARIABLE}
${CMAKE_BINARY_DIR}
${CMAKE_ROOT}/Modules/CheckVariableExists.c
CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_VARIABLE_DEFINITIONS}
${CHECK_VARIABLE_EXISTS_ADD_LIBRARIES}
OUTPUT_VARIABLE OUTPUT)
IF(${VARIABLE})
SET(${VARIABLE} 1 CACHE INTERNAL "Have variable ${VAR}")
MESSAGE(STATUS "Looking for ${VARIABLE} - found")
ELSE(${VARIABLE})
SET(${VARIABLE} "" CACHE INTERNAL "Have variable ${VAR}")
MESSAGE(STATUS "Looking for ${VARIABLE} - not found")
WRITE_FILE(${CMAKE_BINARY_DIR}/CMakeError.log
"Determining if the variable ${VAR} exists failed with the following output:\n"
"${OUTPUT}\n" APPEND)
ENDIF(${VARIABLE})
ENDIF("${VARIABLE}" MATCHES "^${VARIABLE}$")
ENDMACRO(CHECK_VARIABLE_EXISTS)