1 # - Check if the variable exists.
2 # CHECK_VARIABLE_EXISTS(VAR VARIABLE)
4 # VAR - the name of the variable
5 # VARIABLE - variable to store the result
7 # This macro is only for C variables.
9 # The following variables may be set before calling this macro to
10 # modify the way the check is run:
12 # CMAKE_REQUIRED_FLAGS = string of compile command line flags
13 # CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)
14 # CMAKE_REQUIRED_LIBRARIES = list of libraries to link
16 #=============================================================================
17 # Copyright 2002-2009 Kitware, Inc.
19 # Distributed under the OSI-approved BSD License (the "License");
20 # see accompanying file Copyright.txt for details.
22 # This software is distributed WITHOUT ANY WARRANTY; without even the
23 # implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
24 # See the License for more information.
25 #=============================================================================
26 # (To distribute this file outside of CMake, substitute the full
27 # License text for the above reference.)
31 macro(CHECK_VARIABLE_EXISTS VAR VARIABLE)
32 if("${VARIABLE}" MATCHES "^${VARIABLE}$")
33 set(MACRO_CHECK_VARIABLE_DEFINITIONS
34 "-DCHECK_VARIABLE_EXISTS=${VAR} ${CMAKE_REQUIRED_FLAGS}")
35 message(STATUS "Looking for ${VAR}")
36 if(CMAKE_REQUIRED_LIBRARIES)
37 set(CHECK_VARIABLE_EXISTS_ADD_LIBRARIES
38 LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
40 set(CHECK_VARIABLE_EXISTS_ADD_LIBRARIES)
42 try_compile(${VARIABLE}
44 ${CMAKE_ROOT}/Modules/CheckVariableExists.c
45 COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
46 ${CHECK_VARIABLE_EXISTS_ADD_LIBRARIES}
47 CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_VARIABLE_DEFINITIONS}
48 OUTPUT_VARIABLE OUTPUT)
50 set(${VARIABLE} 1 CACHE INTERNAL "Have variable ${VAR}")
51 message(STATUS "Looking for ${VAR} - found")
52 file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
53 "Determining if the variable ${VAR} exists passed with the following output:\n"
56 set(${VARIABLE} "" CACHE INTERNAL "Have variable ${VAR}")
57 message(STATUS "Looking for ${VAR} - not found")
58 file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
59 "Determining if the variable ${VAR} exists failed with the following output:\n"