166 lines
5.9 KiB
CMake
166 lines
5.9 KiB
CMake
# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
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# file Copyright.txt or https://cmake.org/licensing for details.
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#[=======================================================================[.rst:
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CheckSymbolExists
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-----------------
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Provides a macro to check if a symbol exists as a function, variable,
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or macro in ``C``.
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.. command:: check_symbol_exists
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.. code-block:: cmake
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check_symbol_exists(<symbol> <files> <variable>)
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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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``<variable>`` will be created as an internal cache variable.
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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 symbol
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as a function or variable then the symbol must also be available for
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linking (so intrinsics may not be detected).
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If the symbol is a type, enum value, or intrinsic it will not be recognized
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(consider using :module:`CheckTypeSize` or :module:`CheckCSourceCompiles`).
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If the check needs to be done in C++, consider using
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:module:`CheckCXXSymbolExists` instead.
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The following variables may be set before calling this macro to modify
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the way the check is run:
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``CMAKE_REQUIRED_FLAGS``
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string of compile command line flags.
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``CMAKE_REQUIRED_DEFINITIONS``
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a :ref:`;-list <CMake Language Lists>` of macros to define (-DFOO=bar).
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``CMAKE_REQUIRED_INCLUDES``
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a :ref:`;-list <CMake Language Lists>` of header search paths to pass to
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the compiler.
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``CMAKE_REQUIRED_LINK_OPTIONS``
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a :ref:`;-list <CMake Language Lists>` of options to add to the link command.
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``CMAKE_REQUIRED_LIBRARIES``
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a :ref:`;-list <CMake Language Lists>` of libraries to add to the link
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command. See policy :policy:`CMP0075`.
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``CMAKE_REQUIRED_QUIET``
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execute quietly without messages.
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For example:
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.. code-block:: cmake
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include(CheckSymbolExists)
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# Check for macro SEEK_SET
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check_symbol_exists(SEEK_SET "stdio.h" HAVE_SEEK_SET)
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# Check for function fopen
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check_symbol_exists(fopen "stdio.h" HAVE_FOPEN)
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#]=======================================================================]
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include_guard(GLOBAL)
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cmake_policy(PUSH)
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cmake_policy(SET CMP0054 NEW) # if() quoted variables not dereferenced
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macro(CHECK_SYMBOL_EXISTS SYMBOL FILES VARIABLE)
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if(CMAKE_C_COMPILER_LOADED)
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__CHECK_SYMBOL_EXISTS_IMPL("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.c" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
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elseif(CMAKE_CXX_COMPILER_LOADED)
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__CHECK_SYMBOL_EXISTS_IMPL("${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckSymbolExists.cxx" "${SYMBOL}" "${FILES}" "${VARIABLE}" )
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else()
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message(FATAL_ERROR "CHECK_SYMBOL_EXISTS needs either C or CXX language enabled")
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endif()
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endmacro()
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macro(__CHECK_SYMBOL_EXISTS_IMPL SOURCEFILE SYMBOL FILES VARIABLE)
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if(NOT DEFINED "${VARIABLE}" OR "x${${VARIABLE}}" STREQUAL "x${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_LINK_OPTIONS)
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set(CHECK_SYMBOL_EXISTS_LINK_OPTIONS
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LINK_OPTIONS ${CMAKE_REQUIRED_LINK_OPTIONS})
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else()
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set(CHECK_SYMBOL_EXISTS_LINK_OPTIONS)
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endif()
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if(CMAKE_REQUIRED_LIBRARIES)
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set(CHECK_SYMBOL_EXISTS_LIBS
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LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
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else()
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set(CHECK_SYMBOL_EXISTS_LIBS)
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endif()
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if(CMAKE_REQUIRED_INCLUDES)
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set(CMAKE_SYMBOL_EXISTS_INCLUDES
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"-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
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else()
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set(CMAKE_SYMBOL_EXISTS_INCLUDES)
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endif()
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foreach(FILE ${FILES})
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string(APPEND CMAKE_CONFIGURABLE_FILE_CONTENT
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"#include <${FILE}>\n")
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endforeach()
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string(APPEND CMAKE_CONFIGURABLE_FILE_CONTENT "
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int main(int argc, char** argv)
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{
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(void)argv;")
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set(_CSE_CHECK_NON_MACRO "return ((int*)(&${SYMBOL}))[argc];")
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if("${SYMBOL}" MATCHES "^[a-zA-Z_][a-zA-Z0-9_]*$")
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# The SYMBOL has a legal macro name. Test whether it exists as a macro.
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string(APPEND CMAKE_CONFIGURABLE_FILE_CONTENT "
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#ifndef ${SYMBOL}
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${_CSE_CHECK_NON_MACRO}
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#else
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(void)argc;
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return 0;
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#endif")
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else()
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# The SYMBOL cannot be a macro (e.g., a template function).
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string(APPEND CMAKE_CONFIGURABLE_FILE_CONTENT "
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${_CSE_CHECK_NON_MACRO}")
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endif()
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string(APPEND CMAKE_CONFIGURABLE_FILE_CONTENT "
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}")
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unset(_CSE_CHECK_NON_MACRO)
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configure_file("${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in"
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"${SOURCEFILE}" @ONLY)
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if(NOT CMAKE_REQUIRED_QUIET)
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message(CHECK_START "Looking for ${SYMBOL}")
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endif()
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try_compile(${VARIABLE}
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${CMAKE_BINARY_DIR}
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"${SOURCEFILE}"
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COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
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${CHECK_SYMBOL_EXISTS_LINK_OPTIONS}
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${CHECK_SYMBOL_EXISTS_LIBS}
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CMAKE_FLAGS
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-DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_SYMBOL_EXISTS_FLAGS}
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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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if(NOT CMAKE_REQUIRED_QUIET)
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message(CHECK_PASS "found")
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endif()
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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()
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if(NOT CMAKE_REQUIRED_QUIET)
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message(CHECK_FAIL "not found")
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endif()
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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()
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unset(CMAKE_CONFIGURABLE_FILE_CONTENT)
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endif()
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endmacro()
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cmake_policy(POP)
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