| # - Check if a C function can be linked |
| # CHECK_FUNCTION_EXISTS(<function> <variable>) |
| # |
| # Check that the <function> is provided by libraries on the system and |
| # store the result in a <variable>. This does not verify that any |
| # system header file declares the function, only that it can be found |
| # at link time (consider using CheckSymbolExists). |
| # |
| # 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 |
| |
| #============================================================================= |
| # Copyright 2002-2011 Kitware, Inc. |
| # |
| # Distributed under the OSI-approved BSD License (the "License"); |
| # see accompanying file Copyright.txt for details. |
| # |
| # This software is distributed WITHOUT ANY WARRANTY; without even the |
| # implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
| # See the License for more information. |
| #============================================================================= |
| # (To distribute this file outside of CMake, substitute the full |
| # License text for the above reference.) |
| |
| |
| |
| macro(CHECK_FUNCTION_EXISTS FUNCTION VARIABLE) |
| if("${VARIABLE}" MATCHES "^${VARIABLE}$") |
| set(MACRO_CHECK_FUNCTION_DEFINITIONS |
| "-DCHECK_FUNCTION_EXISTS=${FUNCTION} ${CMAKE_REQUIRED_FLAGS}") |
| message(STATUS "Looking for ${FUNCTION}") |
| if(CMAKE_REQUIRED_LIBRARIES) |
| set(CHECK_FUNCTION_EXISTS_ADD_LIBRARIES |
| LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES}) |
| else() |
| set(CHECK_FUNCTION_EXISTS_ADD_LIBRARIES) |
| endif() |
| if(CMAKE_REQUIRED_INCLUDES) |
| set(CHECK_FUNCTION_EXISTS_ADD_INCLUDES |
| "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}") |
| else() |
| set(CHECK_FUNCTION_EXISTS_ADD_INCLUDES) |
| endif() |
| try_compile(${VARIABLE} |
| ${CMAKE_BINARY_DIR} |
| ${CMAKE_ROOT}/Modules/CheckFunctionExists.c |
| COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS} |
| ${CHECK_FUNCTION_EXISTS_ADD_LIBRARIES} |
| CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_FUNCTION_DEFINITIONS} |
| "${CHECK_FUNCTION_EXISTS_ADD_INCLUDES}" |
| OUTPUT_VARIABLE OUTPUT) |
| if(${VARIABLE}) |
| set(${VARIABLE} 1 CACHE INTERNAL "Have function ${FUNCTION}") |
| message(STATUS "Looking for ${FUNCTION} - found") |
| file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log |
| "Determining if the function ${FUNCTION} exists passed with the following output:\n" |
| "${OUTPUT}\n\n") |
| else() |
| message(STATUS "Looking for ${FUNCTION} - not found") |
| set(${VARIABLE} "" CACHE INTERNAL "Have function ${FUNCTION}") |
| file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log |
| "Determining if the function ${FUNCTION} exists failed with the following output:\n" |
| "${OUTPUT}\n\n") |
| endif() |
| endif() |
| endmacro() |