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一、官方cmake配置命令使用方法

授人以鱼不如授人以渔，大家可以在官网找到命令的更多细节，可以边用边找。 这里主要可以看到以下五个部分的命令，大家根据需求自行搜索

1. 脚本命令/Scripting Commands

这些命令总是可用的。

block	break	cmake_host_system_information	cmake_language
cmake_minimum_required	cmake_parse_arguments	cmake_path	cmake_policy
configure_file	continue	else	elseif
endblock	endforeach	endfunction	endif
endmacro	endwhile	execute_process	file
find_file	find_library	find_package	find_path
find_program	foreach	function	get_cmake_property
get_directory_property	get_filename_component	get_property	if
include	include_guard	list	macro
mark_as_advanced	math	message	option
return	separate_arguments	set	set_directory_properties
set_property	site_name	string	unset
variable_watch	while

2. 工程命令/Project Commands

这些命令只在CMake项目中可用。

add_compile_definitions	add_compile_options	add_custom_command	add_custom_target
add_definitions	add_dependencies	add_executable	add_library
add_link_options	add_subdirectory	add_test	aux_source_directory
build_command	create_test_sourcelist	define_property	enable_language
enable_testing	export	fltk_wrap_ui	get_source_file_property
get_target_property	get_test_property	include_directories	include_external_msproject
include_regular_expression	install	link_directories	link_libraries
load_cache	project	remove_definitions	set_source_files_properties
set_target_properties	set_tests_properties	source_group	target_compile_definitions
target_compile_features	target_compile_options	target_include_directories	target_link_directories
target_link_libraries	target_link_options	target_precompile_headers	target_sources
try_compile	try_run

3. CTest脚本命令/CTest Commands

这些命令只在CTest脚本中可用。

4. Deprecated Commands

这些命令已被弃用，仅用于维护向后兼容性。每个命令的文档都说明了它被弃用的CMake版本。不要在新代码中使用这些命令。

5. CMake中预设的一些变量

例如，我们经常用到的 CMAKE_BINARY_DIR 、 CMAKE_PROJECT_NAME、 CMAKE_PREFIX_PATH 等都可以在这里找到，可以根据我们的需求自行查询。

二、"CMakeLists.txt" 组织大型工程常用命令模板总结

1. cmake_minimum_required

# Setup the minimum version required of CMake to generate the Makefile
# 设置cmake最小版本号
cmake_minimum_required (VERSION 2.8)

# Raises a FATAL_ERROR if version < 2.8
#  不满足提示错误
cmake_minimum_required (VERSION 2.8 FATAL_ERROR)

2. project

# We define the name of our project, and this changes some directories
# naming convention generated by CMake. We can send the LANG of code
# as the second param
# 设置项目名称，指定语言（这里是CXX，也就是C++）
project (learncmake CXX)

3. set

# 给变量赋值
# Set the project source dir (just convention)
# 源码目录
set( LEARN_CMAKE_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR} )
# 目标二进制文件的目录
set( LEARN_CMAKE_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR} )

# 设置语义版本
# It's useful to set up the current version of our code in the build system
# using a `semver` style
set (LEARN_CMAKE_VERSION_MAJOR 1)
set (LEARN_CMAKE_VERSION_MINOR 0)
set (LEARN_CMAKE_VERSION_PATCH 0)

4. configure_file

# 将文件复制到另一个位置并修改其内容，比如管理版本号，打包管理等
# Send the variables (version number) to the source code header
configure_file (
  "${PROJECT_SOURCE_DIR}/TutorialConfig.h.in"
  "${PROJECT_BINARY_DIR}/TutorialConfig.h"
)

5. include_directories

# 包含目录，指定目录，给预编译器做头文件搜索
# Include Directories
# In GCC, this will invoke the "-I" command
include_directories( include )
include_directories(./ ./hello ./world)

6. CMAKE_MODULE_PATH

# CMake的模块化，有多个模块；
# 通过 CMAKE_MODULE_PATH 配置寻找模块的路径，可以写CMake自带的，还可以添加自己的
# Where are the additional libraries installed? Note: provide includes
# path here, subsequent checks will resolve everything else
set( CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/CMake/modules/" )

7. Conditions

if ( CONDITION )
  # Output!

  # Incidental information
  message(STATUS "My message")

  # CMake Warning, continue processing
  message(WARNING "My message")

  # CMake Warning (dev), continue processing
  message(AUTHOR_WARNING "My message")

  # CMake Error, continue processing, but skip generation
  message(SEND_ERROR "My message")

  # CMake Error, stop processing and generation
  message(FATAL_ERROR "My message")
endif()

if( CONDITION )

elseif( CONDITION )

else( CONDITION )

endif( CONDITION )

8. 循环

8.1 foreach()...endforeach()

foreach(loop_var arg1 arg2 ...)
  COMMAND1(ARGS ...)
  COMMAND2(ARGS ...)
  ...
endforeach(loop_var)

foreach(loop_var RANGE total)
foreach(loop_var RANGE start stop [step])

foreach(loop_var IN [LISTS [list1 [...]]]
                    [ITEMS [item1 [...]]])

8.2 while()...endwhile()

while(condition)
  COMMAND1(ARGS ...)
  COMMAND2(ARGS ...)
  ...
endwhile(condition)

9. 逻辑运算：AND、OR

if(FALSE AND (FALSE OR TRUE))
  message("Don't display!")
endif()

# Set a regular, cache, or environment variable to a given value.
# If the PARENT_SCOPE option is given, the variable will be set in the scope
# above the current scope.
# `set(<variable> <value>... [PARENT_SCOPE])`

# How to reference variables inside quoted and unquoted arguments?
# A variable reference is replaced by either the variable value or by the 
# empty string if the variable is not set.
${variable_name}

10. Lists：使用 set 把多个文件赋值给列表型变量

# Setup the list of source files
set( LEARN_CMAKE_SOURCES 
  src/main.c
  src/imagem.c
  src/pather.c
)

11. add_executable

# 指定编译构建的可执行的目标
# Calls the compiler

# ${PROJECT_NAME} 指代项目名称 Learn_CMake 
add_executable( ${PROJECT_NAME} ${LEARN_CMAKE_SOURCES} )

12. add_library

# 添加库文件
add_library()

13. add_subdirectory

# 添加模块子目录
# Add block directories
add_subdirectory(hello)
add_subdirectory(world)

14. target_link_libraries

# 链接库
# Link the libraries
target_link_libraries( ${PROJECT_NAME} ${LIBS} m )

15. Compiler Condition (gcc ; g++)

if ( "${CMAKE_C_COMPILER_ID}" STREQUAL "GNU" )
  message( STATUS "Setting the flags for ${CMAKE_C_COMPILER_ID} compiler" )
  add_definitions( --std=c99 )
endif()

16. 编译系统（OS）的判断

if( UNIX )
    set( LEARN_CMAKE_DEFINITIONS
        "${LEARN_CMAKE_DEFINITIONS} -Wall -Wextra -Werror -Wno-deprecated-declarations -Wno-unused-parameter -Wno-comment" )
endif()

三、区分

include_directories	add_subdirectory	add_library
向构建中添加包含目录	向构建添加子目录	使用指定的源文件向项目添加库
		正常库/对象库/接口库/导入库/别名库