813eca6416
Otherwise the compiler may optimize out the reference to the symbol as the previous version was not really using this. This leads to symbols that are only in a header but not in the given libraries to be reported as present. This came up on the first try to fix bug 11333 as "gcc -O3" would optimize out the reference to pthread_create() so the correct library the symbol is in was not detected. The new test code was suggested by Brad King.
97 lines
4.4 KiB
CMake
97 lines
4.4 KiB
CMake
# - Check if a symbol exists as a function, variable, or macro
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# CHECK_SYMBOL_EXISTS(<symbol> <files> <variable>)
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#
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# Check that the <symbol> is available after including given header
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# <files> and store the result in a <variable>. Specify the list
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# of files in one argument as a semicolon-separated list.
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#
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# If the header files define the symbol as a macro it is considered
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# available and assumed to work. If the header files declare the
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# symbol as a function or variable then the symbol must also be
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# available for linking. If the symbol is a type or enum value
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# it will not be recognized (consider using CheckTypeSize or
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# CheckCSourceCompiles).
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# If the check needs to be done in C++, consider using CHECK_CXX_SYMBOL_EXISTS(),
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# which does the same as CHECK_SYMBOL_EXISTS(), but in C++.
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#
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# The following variables may be set before calling this macro to
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# modify the way the check is run:
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#
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# CMAKE_REQUIRED_FLAGS = string of compile command line flags
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# CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)
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# CMAKE_REQUIRED_INCLUDES = list of include directories
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# CMAKE_REQUIRED_LIBRARIES = list of libraries to link
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#=============================================================================
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# Copyright 2003-2011 Kitware, Inc.
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#
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# Distributed under the OSI-approved BSD License (the "License");
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# see accompanying file Copyright.txt for details.
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#
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# This software is distributed WITHOUT ANY WARRANTY; without even the
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# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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# See the License for more information.
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#=============================================================================
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# (To distribute this file outside of CMake, substitute the full
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# License text for the above reference.)
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MACRO(CHECK_SYMBOL_EXISTS SYMBOL FILES VARIABLE)
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_CHECK_SYMBOL_EXISTS("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.c" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
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ENDMACRO(CHECK_SYMBOL_EXISTS)
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MACRO(_CHECK_SYMBOL_EXISTS SOURCEFILE SYMBOL FILES VARIABLE)
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IF("${VARIABLE}" MATCHES "^${VARIABLE}$")
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SET(CMAKE_CONFIGURABLE_FILE_CONTENT "/* */\n")
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SET(MACRO_CHECK_SYMBOL_EXISTS_FLAGS ${CMAKE_REQUIRED_FLAGS})
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IF(CMAKE_REQUIRED_LIBRARIES)
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SET(CHECK_SYMBOL_EXISTS_LIBS
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"-DLINK_LIBRARIES:STRING=${CMAKE_REQUIRED_LIBRARIES}")
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ELSE(CMAKE_REQUIRED_LIBRARIES)
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SET(CHECK_SYMBOL_EXISTS_LIBS)
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ENDIF(CMAKE_REQUIRED_LIBRARIES)
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IF(CMAKE_REQUIRED_INCLUDES)
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SET(CMAKE_SYMBOL_EXISTS_INCLUDES
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"-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
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ELSE(CMAKE_REQUIRED_INCLUDES)
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SET(CMAKE_SYMBOL_EXISTS_INCLUDES)
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ENDIF(CMAKE_REQUIRED_INCLUDES)
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FOREACH(FILE ${FILES})
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SET(CMAKE_CONFIGURABLE_FILE_CONTENT
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"${CMAKE_CONFIGURABLE_FILE_CONTENT}#include <${FILE}>\n")
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ENDFOREACH(FILE)
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SET(CMAKE_CONFIGURABLE_FILE_CONTENT
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"${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")
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CONFIGURE_FILE("${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in"
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"${SOURCEFILE}" @ONLY IMMEDIATE)
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MESSAGE(STATUS "Looking for ${SYMBOL}")
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TRY_COMPILE(${VARIABLE}
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${CMAKE_BINARY_DIR}
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"${SOURCEFILE}"
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COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
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CMAKE_FLAGS
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-DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_SYMBOL_EXISTS_FLAGS}
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"${CHECK_SYMBOL_EXISTS_LIBS}"
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"${CMAKE_SYMBOL_EXISTS_INCLUDES}"
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OUTPUT_VARIABLE OUTPUT)
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IF(${VARIABLE})
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MESSAGE(STATUS "Looking for ${SYMBOL} - found")
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SET(${VARIABLE} 1 CACHE INTERNAL "Have symbol ${SYMBOL}")
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FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
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"Determining if the ${SYMBOL} "
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"exist passed with the following output:\n"
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"${OUTPUT}\nFile ${SOURCEFILE}:\n"
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"${CMAKE_CONFIGURABLE_FILE_CONTENT}\n")
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ELSE(${VARIABLE})
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MESSAGE(STATUS "Looking for ${SYMBOL} - not found.")
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SET(${VARIABLE} "" CACHE INTERNAL "Have symbol ${SYMBOL}")
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FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
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"Determining if the ${SYMBOL} "
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"exist failed with the following output:\n"
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"${OUTPUT}\nFile ${SOURCEFILE}:\n"
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"${CMAKE_CONFIGURABLE_FILE_CONTENT}\n")
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ENDIF(${VARIABLE})
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ENDIF("${VARIABLE}" MATCHES "^${VARIABLE}$")
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ENDMACRO(_CHECK_SYMBOL_EXISTS)
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