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- #.rst:
- # CheckSymbolExists
- # -----------------
- #
- # Check if a symbol exists as a function, variable, or macro
- #
- # CHECK_SYMBOL_EXISTS(<symbol> <files> <variable>)
- #
- # Check that the <symbol> is available after including given header
- # <files> and store the result in a <variable>. Specify the list of
- # files in one argument as a semicolon-separated list.
- # <variable> will be created as an internal cache variable.
- #
- # If the header files define the symbol as a macro it is considered
- # available and assumed to work. If the header files declare the symbol
- # as a function or variable then the symbol must also be available for
- # linking. If the symbol is a type or enum value it will not be
- # recognized (consider using CheckTypeSize or CheckCSourceCompiles). If
- # the check needs to be done in C++, consider using
- # CHECK_CXX_SYMBOL_EXISTS(), which does the same as
- # CHECK_SYMBOL_EXISTS(), but in C++.
- #
- # 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
- # CMAKE_REQUIRED_QUIET = execute quietly without messages
- #=============================================================================
- # Copyright 2003-2011 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_SYMBOL_EXISTS SYMBOL FILES VARIABLE)
- if(CMAKE_C_COMPILER_LOADED)
- _CHECK_SYMBOL_EXISTS("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.c" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
- elseif(CMAKE_CXX_COMPILER_LOADED)
- _CHECK_SYMBOL_EXISTS("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
- else()
- message(FATAL_ERROR "CHECK_SYMBOL_EXISTS needs either C or CXX language enabled")
- endif()
- endmacro()
- macro(_CHECK_SYMBOL_EXISTS SOURCEFILE SYMBOL FILES VARIABLE)
- if(NOT DEFINED "${VARIABLE}" OR "x${${VARIABLE}}" STREQUAL "x${VARIABLE}")
- set(CMAKE_CONFIGURABLE_FILE_CONTENT "/* */\n")
- set(MACRO_CHECK_SYMBOL_EXISTS_FLAGS ${CMAKE_REQUIRED_FLAGS})
- if(CMAKE_REQUIRED_LIBRARIES)
- set(CHECK_SYMBOL_EXISTS_LIBS
- LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
- else()
- set(CHECK_SYMBOL_EXISTS_LIBS)
- endif()
- if(CMAKE_REQUIRED_INCLUDES)
- set(CMAKE_SYMBOL_EXISTS_INCLUDES
- "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
- else()
- set(CMAKE_SYMBOL_EXISTS_INCLUDES)
- endif()
- foreach(FILE ${FILES})
- set(CMAKE_CONFIGURABLE_FILE_CONTENT
- "${CMAKE_CONFIGURABLE_FILE_CONTENT}#include <${FILE}>\n")
- endforeach()
- set(CMAKE_CONFIGURABLE_FILE_CONTENT
- "${CMAKE_CONFIGURABLE_FILE_CONTENT}\nint main(int argc, char** argv)\n{\n (void)argv;\n#ifndef ${SYMBOL}\n return ((int*)(&${SYMBOL}))[argc];\n#else\n (void)argc;\n return 0;\n#endif\n}\n")
- configure_file("${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in"
- "${SOURCEFILE}" @ONLY)
- if(NOT CMAKE_REQUIRED_QUIET)
- message(STATUS "Looking for ${SYMBOL}")
- endif()
- try_compile(${VARIABLE}
- ${CMAKE_BINARY_DIR}
- "${SOURCEFILE}"
- COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
- ${CHECK_SYMBOL_EXISTS_LIBS}
- CMAKE_FLAGS
- -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_SYMBOL_EXISTS_FLAGS}
- "${CMAKE_SYMBOL_EXISTS_INCLUDES}"
- OUTPUT_VARIABLE OUTPUT)
- if(${VARIABLE})
- if(NOT CMAKE_REQUIRED_QUIET)
- message(STATUS "Looking for ${SYMBOL} - found")
- endif()
- set(${VARIABLE} 1 CACHE INTERNAL "Have symbol ${SYMBOL}")
- file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
- "Determining if the ${SYMBOL} "
- "exist passed with the following output:\n"
- "${OUTPUT}\nFile ${SOURCEFILE}:\n"
- "${CMAKE_CONFIGURABLE_FILE_CONTENT}\n")
- else()
- if(NOT CMAKE_REQUIRED_QUIET)
- message(STATUS "Looking for ${SYMBOL} - not found")
- endif()
- set(${VARIABLE} "" CACHE INTERNAL "Have symbol ${SYMBOL}")
- file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
- "Determining if the ${SYMBOL} "
- "exist failed with the following output:\n"
- "${OUTPUT}\nFile ${SOURCEFILE}:\n"
- "${CMAKE_CONFIGURABLE_FILE_CONTENT}\n")
- endif()
- endif()
- endmacro()
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