====== CMake ======
  * Official Site:[[https://cmake.org/|cmake.org]]   
  * c++跨平台构建工具,开源[BSD]免费。
  * CMake [[https://cmake.org/cmake/help/latest/manual/cmake-variables.7.html|变量列表]]:
  * CMake 变量的作用域：[[https://cmake.org/cmake/help/latest/manual/cmake-language.7.html#cmake-language-variables|cmake-language-variables]]
    * 父目录里的绑定变量默认会传到子目录的CMakefile作为初始值
===== Tips =====
  * MSVC中， cmake 默认生成的 release 工程不生成 pdb 文件，可如下添加<code cmake>
if (MSVC)
    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Zi")
    # if build .exe  
    set(CMAKE_EXE_LINKER_FLAGS_RELEASE"${CMAKE_EXE_LINKER_FLAGS_RELEASE} /DEBUG /OPT:REF /OPT:ICF" CACHE STRING "" FORCE)
    # if build .dll   
    set(CMAKE_SHARED_LINKER_FLAGS_RELEASE  "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} /DEBUG /OPT:REF /OPT:ICF" CACHE STRING "" FORCE)
    # if build static .lib 
    set(CMAKE_STATIC_LINKER_FLAGS_RELEASE "${CMAKE_STATIC_LINKER_FLAGS_RELEASE} /DEBUG /OPT:REF /OPT:ICF" CACHE STRING "" FORCE)
endif (MSVC)
</code> 参考 [[https://stackoverflow.com/questions/28178978/how-to-generate-pdb-files-for-release-build-with-cmake-flags/31264946|how to generate pdb files...]], 或者使用 [[https://cmake.org/cmake/help/v3.18/manual/cmake-generator-expressions.7.html|cmake generator expressions]]来设置:<code cmake>
target_compile_options(${YourProjName} 
    PRIVATE "$<$<AND:$<CXX_COMPILER_ID:MSVC>,$<CONFIG:Release>>:/Zi>"
)
target_link_options(${YourProjName}
    PRIVATE "$<$<AND:$<CXX_COMPILER_ID:MSVC>,$<CONFIG:Release>>:/DEBUG>"
    PRIVATE "$<$<AND:$<CXX_COMPILER_ID:MSVC>,$<CONFIG:Release>>:/OPT:REF>"
    PRIVATE "$<$<AND:$<CXX_COMPILER_ID:MSVC>,$<CONFIG:Release>>:/OPT:ICF>"
)
</code>
  * 给dll右键属性的详细信息里添加git version, 参考[[https://zhuanlan.zhihu.com/p/97512450|zhihu 97512450]]<code cmake>
add_definitions(-DMAIN_PROJECT_NAME=\"${YourProjName}\")
find_package(Git QUIET)
if(GIT_FOUND)
    set(COMMIT_HASH "")
    set(BRANCH_NAME "")
    execute_process(
        COMMAND ${GIT_EXECUTABLE} log -1 --pretty=format:%H
        OUTPUT_VARIABLE COMMIT_HASH
        OUTPUT_STRIP_TRAILING_WHITESPACE
        ERROR_QUIET
        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    )
    execute_process(
        COMMAND ${GIT_EXECUTABLE} symbolic-ref --short -q HEAD
        OUTPUT_VARIABLE BRANCH_NAME
        OUTPUT_STRIP_TRAILING_WHITESPACE
        ERROR_QUIET
        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    )
    message(STATUS "Git version is ${BRANCH_NAME}:${COMMIT_HASH}")
    add_definitions(-DGIT_COMMIT_HASH=\"${COMMIT_HASH}\")
    add_definitions(-DGIT_BRANCH_NAME=\"${BRANCH_NAME}\")
endif()
</code>然后添加VersionInfo.rc<code>

#if (defined GIT_COMMIT_HASH && defined GIT_BRANCH_NAME)
#define PRODUCT_VERSION GIT_BRANCH_NAME ":" GIT_COMMIT_HASH
#else
#define PRODUCT_VERSION "1.0.2"
#endif //  GIT_COMMIT_HASH && GIT_BRANCH_NAME

#ifndef MAIN_PROJECT_NAME
#define MAIN_PROJECT_NAME "MyLib"
#endif

1 VERSIONINFO
	FILEVERSION 1,0,0,1
	PRODUCTVERSION 1,0,0,1
	FILEFLAGSMASK 0x17L
#ifdef _DEBUG
	FILEFLAGS 0x1L
#else
	FILEFLAGS 0x0L
#endif
	FILEOS 0x4L
	FILETYPE 0x0L
	FILESUBTYPE 0x0L
BEGIN
	BLOCK "StringFileInfo"
	BEGIN
		BLOCK "040904b0"
		BEGIN
			VALUE "FileDescription", MAIN_PROJECT_NAME " Binary"
			VALUE "FileVersion", "1.0.0.1"
			VALUE "InternalName", MAIN_PROJECT_NAME
			VALUE "LegalCopyright", "Copyright (C) 2020 "
			VALUE "OriginalFilename", MAIN_PROJECT_NAME ".dll"
			VALUE "ProductName", MAIN_PROJECT_NAME
			VALUE "ProductVersion", PRODUCT_VERSION
		END
	END
	BLOCK "VarFileInfo"
	BEGIN
		VALUE "Translation", 0x409, 1200
	END
END
</code>
  * 循环子文件夹来包含子工程，参考 [[https://stackoverflow.com/questions/7787823/cmake-how-to-get-the-name-of-all-subdirectories-of-a-directory|stackoverflow 7787823]]：<code cmake>
MACRO(SUBDIRLIST result curdir)
  FILE(GLOB children RELATIVE ${curdir} ${curdir}/*)
  SET(dirlist "")
  FOREACH(child ${children})
    IF(IS_DIRECTORY ${curdir}/${child} AND EXISTS ${curdir}/${child}/CMakeLists.txt)
        LIST(APPEND dirlist ${child})
    ENDIF()
  ENDFOREACH()
  SET(${result} ${dirlist})
ENDMACRO()

SUBDIRLIST(SUBDIRS ${CMAKE_CURRENT_SOURCE_DIR})

message(STATUS "valid subdirs: ${SUBDIRS}")

FOREACH(subdir ${SUBDIRS})
  ADD_SUBDIRECTORY(${subdir})
ENDFOREACH()
</code>
  * 在 bat 批处理里面，如果cmake命令行报错，参考[[https://stackoverflow.com/questions/46709956/how-do-i-handle-cmake-exe-errors|这里]]，可加以下一行来进行退出处理<code Winbatch >
cmake .
if errorlevel 1 exit /B
</code>
  * 屏蔽VC编译 release 时的具体某个 warning，比如c4566, 可用如下，<code cmake>
add_compile_options("$<$<AND:$<CXX_COMPILER_ID:MSVC>,$<CONFIG:Release>>:/wd4566>")
</code> 注意 ''add_compile_options'' 可影响之后所有target与子项目target, 所以适合在ci(持续集成)时使用。如果只是想具体设置某target, 使用 ''target_compile_options''。另外，不建议开发时屏蔽warning。
  * cmake 不支持静态库的 dependence, 本质上，静态库只有二进制的合并，没有 link, 只有MSVC可以加 静态库的dependence然后生成合并后的lib, 但这个其它编译器不一定支持，所以cmake也没有这个选项，如果生成的 a.lib 依赖b.lib, 而 c.exe 依赖 a.lib, 一种不用在 c 的配置中显式增加 b.lib 依赖的写法是利用 ''add_library(<name> INTERFACE)'': <code cmake>
add_library(a STATIC  ${STRMBASE_FILES})
# target_link_libraries(a b) # 这是不起作用的，因为 a 是静态库，没有link
add_library(ab INTERFACE) # 增加一个 ab, INTERFACE 
target_link_libraries(ab INTERFACE a b)
add_executable(c ...)
target_link_libraries(c ab) # 此时 c 工程就包含了a.lib, b.lib
</code>
  * [[https://stackoverflow.com/questions/26037954/cmake-target-link-libraries-interface-dependencies|target_link_libraries PUBLIC/PRIVATE/INTERFACE 的区别]]：当创建**动态库**时，
    * 如果源文件包含该第三方头文件，但头文件中不包含该第三方头文件，采用 PRIVATE；
    * 如果源文件和头文件中都包含该第三方头文件，采用 PUBLIC；
    * 如果头文件中包含该第三方头文件，但源文件中不包含，采用 INTERFACE。