1772622772
``` git grep -lz 'Copyright.txt or https://cmake.org/licensing ' | while IFS= read -r -d $'\0' f ; do sed -i '/Copyright.txt or https:\/\/cmake.org\/licensing / { s/Copyright.txt/LICENSE.rst/ }' "$f" ; done ```
137 lines
4.4 KiB
CMake
137 lines
4.4 KiB
CMake
# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
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# file LICENSE.rst or https://cmake.org/licensing for details.
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#[=======================================================================[.rst:
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CheckLibraryExists
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------------------
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Check once if the function exists in system or specified library.
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.. command:: check_library_exists
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.. code-block:: cmake
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check_library_exists(<library> <function> <location> <variable>)
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Check that the library ``<library>`` exists in the given location
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``<location>`` and has the specified ``<function>``. The result is stored in
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an internal cache variable ``<variable>``. If ``<location>`` is empty string,
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default directories are searched.
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Prefer using :module:`CheckSymbolExists` or :module:`CheckSourceCompiles`
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instead of this module for more robust detection if a function is available in
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a library.
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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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.. include:: /module/CMAKE_REQUIRED_FLAGS.txt
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.. include:: /module/CMAKE_REQUIRED_DEFINITIONS.txt
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.. include:: /module/CMAKE_REQUIRED_LINK_OPTIONS.txt
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.. include:: /module/CMAKE_REQUIRED_LIBRARIES.txt
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.. include:: /module/CMAKE_REQUIRED_LINK_DIRECTORIES.txt
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.. include:: /module/CMAKE_REQUIRED_QUIET.txt
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Examples
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^^^^^^^^
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This module can be useful for performing so-called sanity checks to verify that
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the specified library provides the expected functionality and is indeed the
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correct one being located.
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For example, to check if the ``curl`` library exists in the default paths and
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has the ``curl_easy_perform`` function:
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.. code-block:: cmake
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include(CheckLibraryExists)
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check_library_exists(curl curl_easy_perform "" HAVE_LIBRARY_CURL)
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To check if library exists in specific non-standard location and has a specified
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function:
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.. code-block:: cmake
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include(CheckLibraryExists)
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check_library_exists(curl curl_easy_perform "/opt/curl/lib" HAVE_LIBRARY_CURL)
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Also :ref:`IMPORTED library <add_library imported libraries>` (for example,
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from the ``find_package()`` call) can be used:
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.. code-block:: cmake
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find_package(CURL)
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# ...
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if(TARGET CURL::libcurl)
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include(CheckLibraryExists)
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check_library_exists(CURL::libcurl curl_easy_perform "" HAVE_LIBRARY_CURL)
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endif()
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#]=======================================================================]
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include_guard(GLOBAL)
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macro(CHECK_LIBRARY_EXISTS LIBRARY FUNCTION LOCATION VARIABLE)
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if(NOT DEFINED "${VARIABLE}")
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set(MACRO_CHECK_LIBRARY_EXISTS_DEFINITION
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"-DCHECK_FUNCTION_EXISTS=${FUNCTION} ${CMAKE_REQUIRED_FLAGS}")
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if(NOT CMAKE_REQUIRED_QUIET)
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message(CHECK_START "Looking for ${FUNCTION} in ${LIBRARY}")
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endif()
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set(CHECK_LIBRARY_EXISTS_LINK_OPTIONS)
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if(CMAKE_REQUIRED_LINK_OPTIONS)
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set(CHECK_LIBRARY_EXISTS_LINK_OPTIONS
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LINK_OPTIONS ${CMAKE_REQUIRED_LINK_OPTIONS})
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endif()
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set(CHECK_LIBRARY_EXISTS_LIBRARIES ${LIBRARY})
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if(CMAKE_REQUIRED_LIBRARIES)
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set(CHECK_LIBRARY_EXISTS_LIBRARIES
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${CHECK_LIBRARY_EXISTS_LIBRARIES} ${CMAKE_REQUIRED_LIBRARIES})
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endif()
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if(CMAKE_REQUIRED_LINK_DIRECTORIES)
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set(_CLE_LINK_DIRECTORIES
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"-DLINK_DIRECTORIES:STRING=${LOCATION};${CMAKE_REQUIRED_LINK_DIRECTORIES}")
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else()
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set(_CLE_LINK_DIRECTORIES "-DLINK_DIRECTORIES:STRING=${LOCATION}")
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endif()
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if(CMAKE_C_COMPILER_LOADED)
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set(_cle_source CheckFunctionExists.c)
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elseif(CMAKE_CXX_COMPILER_LOADED)
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set(_cle_source CheckFunctionExists.cxx)
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else()
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message(FATAL_ERROR "CHECK_FUNCTION_EXISTS needs either C or CXX language enabled")
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endif()
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try_compile(${VARIABLE}
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SOURCE_FROM_FILE "${_cle_source}" "${CMAKE_ROOT}/Modules/CheckFunctionExists.c"
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COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
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${CHECK_LIBRARY_EXISTS_LINK_OPTIONS}
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LINK_LIBRARIES ${CHECK_LIBRARY_EXISTS_LIBRARIES}
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CMAKE_FLAGS
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-DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_LIBRARY_EXISTS_DEFINITION}
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"${_CLE_LINK_DIRECTORIES}"
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)
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unset(_cle_source)
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unset(_CLE_LINK_DIRECTORIES)
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if(${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 library ${LIBRARY}")
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else()
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if(NOT CMAKE_REQUIRED_QUIET)
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message(CHECK_FAIL "not found")
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endif()
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set(${VARIABLE} "" CACHE INTERNAL "Have library ${LIBRARY}")
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endif()
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endif()
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endmacro()
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