cmake:find_package查找pthread for win32的实现脚本

阳光穿透心脏的1/2处 2022-05-08 03:06 323阅读 0赞

[pthread for win32][]本身没有提供find\_package脚本，cmake官方也没有提供，所以如果在cmake中要查找pthread for win32的库，就得自己实现，我参照[FindJPEG.cmake][]自己写了个查找脚本`FindPTHREADW32`。  
cmake官方提供的`FindJPEG.cmake`非常简单，只输出了include文件夹位置和JPEG库文件(`JPEG_INCLUDE_DIR`和`JPEG_LIBRARIES`),在写`FindPTHREADW32`时，为了更方便的引用库，在输出`PTHREADW32_INCLUDE_DIR`和`PTHREADW32_LIBRARY`变量的基础上，还提供了[imported target][]:`pthreadw32`,

有了[imported target][]定义，在cmake脚本中引用库更加方便,示例如下：

if(WIN32)
    	find_package(PTHREADW32 REQUIRED)
    endif(WIN32)
    # 为${_target}添加依赖库pthreadw32
    if(TARGET pthreadw32)
    	target_link_libraries(${_target} PUBLIC pthreadw32)
    elseif(HAVE_PTHREAD)
    	target_link_libraries(${_target} PUBLIC -lpthread)
    endif()

下面是我参照FindJPEG.cmake写的完整的实现代码

# FindPTHREADW32
    # --------
    #
    # Find Pthread for win32
    #
    # Find the native pthread for win32 includes and library This module defines
    #
    # ::
    #
    #   PTHREADW32_INCLUDE_DIR, where to find pthread.h, etc.
    #   PTHREADW32_LIBRARY, where to find the pthread for win32 library.
    #   PTHREADW32_FOUND, If false, do not try to use pthread for win32.
    #   HAVE_PTHREAD, if true, pthread supported by compiler
    #
    #   IMPORTED TARGET: pthreadw32
    #=============================================================================
    
    if(NOT WIN32)
    	return()
    endif()
    # 检查编译器是否支持pthread如果支持就返回, 
    # POSIX版本的MinGW原生支持pthread,不需要额外的pthread for win32库
    include(CheckLibraryExists)
    CHECK_LIBRARY_EXISTS (pthread pthread_rwlock_init "" HAVE_PTHREAD)
    if(HAVE_PTHREAD)
    	message(STATUS "pthread supported")
    	return()
    endif()
    # 查找pthread.h 头文件位置
    find_path(PTHREADW32_INCLUDE_DIR pthread.h)
    set(PTHREADW32_NAME pthread)
    if(MSVC)
    	set(PTHREADW32_NAME pthread.lib pthreadVC2)
    elseif(MINGW)
    	set(PTHREADW32_NAME libpthread.a pthreadGC2)	
    endif()
    if( CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64|x64|AMD64|Win64")
    	set(_arch  "x64")
    elseif(CMAKE_SYSTEM_PROCESSOR MATCHES  "Win32|x86")
    	set(_arch  "x86")
    endif()
    # 查找库文件
    find_library(PTHREADW32_LIBRARY NAMES ${PTHREADW32_NAME} pthread PATH_SUFFIXES lib/${_arch} )
    
    # handle the QUIETLY and REQUIRED arguments and set PTHREADW32_FOUND to TRUE if
    # all listed variables are TRUE
    include(FindPackageHandleStandardArgs)
    FIND_PACKAGE_HANDLE_STANDARD_ARGS(PTHREADW32 DEFAULT_MSG PTHREADW32_LIBRARY PTHREADW32_INCLUDE_DIR)
    
    mark_as_advanced(PTHREADW32_LIBRARY PTHREADW32_INCLUDE_DIR )
    #message(STATUS PTHREADW32_INCLUDE_DIR=${PTHREADW32_INCLUDE_DIR})
    
    if(PTHREADW32_FOUND) 
    	if(MSVC)
    		set(_dll_name pthreadVC2.dll)
    	elseif(MINGW)
    		set(_dll_name pthreadGC2.dll)	
    	endif()
    	find_file(PTHREADW32_DLL ${_dll_name} PATH_SUFFIXES dll/${_arch})
    	#message(STATUS PTHREADW32_DLL=${PTHREADW32_DLL})
    	# 创建imported target
    	add_library(pthreadw32 UNKNOWN IMPORTED)
    	set_target_properties(pthreadw32 PROPERTIES
    	  INTERFACE_INCLUDE_DIRECTORIES "${PTHREADW32_INCLUDE_DIR}"
    	  IMPORTED_LINK_INTERFACE_LANGUAGES "C"
    	  IMPORTED_LOCATION "${PTHREADW32_LIBRARY}"
    	  )
    	
    	# 解决 Visual Studio 2015下编译struct timespec重定义问题
    	if(MSVC)
    		# 检查是否定义了 struct timespec
    		include(CheckStructHasMember)
    		CHECK_STRUCT_HAS_MEMBER("struct timespec" tv_sec time.h HAVE_STRUCT_TIMESPEC LANGUAGE C )  
    		if(HAVE_STRUCT_TIMESPEC)
    			set_target_properties(pthreadw32 PROPERTIES INTERFACE_COMPILE_DEFINITIONS HAVE_STRUCT_TIMESPEC )
    		endif()
    	endif()
    endif()
    
    unset(_arch)

[pthread for win32]: https://www.sourceware.org/pthreads-win32/
[FindJPEG.cmake]: https://cmake.org/cmake/help/v3.1/module/FindJPEG.html
[imported target]: https://cmake.org/cmake/help/v3.1/manual/cmake-buildsystem.7.html#imported-targets