| # - Check if the variable exists. |
| # CHECK_VARIABLE_EXISTS(VAR VARIABLE) |
| # |
| # VAR - the name of the variable |
| # VARIABLE - variable to store the result |
| # |
| # This macro is only for C variables. |
| # |
| # 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_LIBRARIES = list of libraries to link |
| |
| MACRO(CHECK_VARIABLE_EXISTS VAR VARIABLE) |
| IF("${VARIABLE}" MATCHES "^${VARIABLE}$") |
| SET(MACRO_CHECK_VARIABLE_DEFINITIONS |
| "-DCHECK_VARIABLE_EXISTS=${VAR} ${CMAKE_REQUIRED_FLAGS}") |
| MESSAGE(STATUS "Looking for ${VAR}") |
| IF(CMAKE_REQUIRED_LIBRARIES) |
| SET(CHECK_VARIABLE_EXISTS_ADD_LIBRARIES |
| "-DLINK_LIBRARIES:STRING=${CMAKE_REQUIRED_LIBRARIES}") |
| ELSE(CMAKE_REQUIRED_LIBRARIES) |
| SET(CHECK_VARIABLE_EXISTS_ADD_LIBRARIES) |
| ENDIF(CMAKE_REQUIRED_LIBRARIES) |
| TRY_COMPILE(${VARIABLE} |
| ${CMAKE_BINARY_DIR} |
| ${CMAKE_ROOT}/Modules/CheckVariableExists.c |
| COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS} |
| CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${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 ${VAR} - found") |
| FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log |
| "Determining if the variable ${VAR} exists passed with the following output:\n" |
| "${OUTPUT}\n\n") |
| ELSE(${VARIABLE}) |
| SET(${VARIABLE} "" CACHE INTERNAL "Have variable ${VAR}") |
| MESSAGE(STATUS "Looking for ${VAR} - not found") |
| FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log |
| "Determining if the variable ${VAR} exists failed with the following output:\n" |
| "${OUTPUT}\n\n") |
| ENDIF(${VARIABLE}) |
| ENDIF("${VARIABLE}" MATCHES "^${VARIABLE}$") |
| ENDMACRO(CHECK_VARIABLE_EXISTS) |
