CMake语法笔记（1）

cmake_minimum_required(VERSION3.4)
project(hello_cmake)
add_executable(hello_cmake main.cpp)

set（sources src/Hello.cpp src/main.cpp)多个源文件可用此方法。
add_executable(${PROJECT_NAME}${SOURCES})
target_include_directories(hello_headers PRIVATE ${PROJECT_SOURCE_DIR}/include) same as -I/directory/path

add_library(hello_library STATIC src/hello.cpp)生成静态库
target_include_directories(hello_library PUBLIC ${PROJECT_SOURCE_DIR}/include)用pubilc因为不只创建库的时候要用到，创建生成文件还要链接到库。
target_link_libraries(hello_binary PRIVATE hello_library)

add_library(hello_library SHARED src/hello.cpp) 生成动态库
add_library(hell0::library ALIAS hello_library) 给库创建别名

install （指令顺序cmake-make-sudo make install）（先构建，再加下列指令）
install（TARGETS cmake_example_inst_bin DESTINATION bin)

install（TARGETS cmake_example_inst LIBRARY DESTINATION lib)

install（DIRECTORY ${DIRECTORY_SOURCE_DIR}/include/  DESTINATION include)

install（FILES cmake-examples.conf  DESTINATION etc)

添加默认build type

cmake .. -DCMAKE_BUILD_TYPE=Release

• Release -O3 -DNDEBUG

• Debug -g

• MinSizeRel -Os -DNDEBUG

• RelWithDebInfo -O2 -g -DNDEBUG   

if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
  message("Setting build type to 'RelWithDebInfo' as none was specified.")
  set(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "Choose the type of build." FORCE)
  # Set the possible values of build type for cmake-gui
  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release"
    "MinSizeRel" "RelWithDebInfo")
endif()

带-flag编译
target_compile_definitions(cmake_examples_compile_flags
    PRIVATE EX3
)

Find package 第三方库
find_package()会去/usr/share/cmake/Modules找FindXXX.cmake文件。

A basic example of finding boost is below:

find_package(Boost 1.46.1 REQUIRED COMPONENTS filesystem system)

The arguments are:

• Boost - Name of the library. This is part of used to find the module file FindBoost.cmake

• 1.46.1 - The minimum version of boost to find

• REQUIRED - Tells the module that this is required and to fail it it cannot be found

• COMPONENTS - The list of libraries to find.

对于Alies/Imported targets

  target_link_libraries( third_party_include
      PRIVATE
          Boost::filesystem
  )

对于Non-Alies targets

# Include the boost headers
target_include_directories( third_party_include
    PRIVATE ${Boost_INCLUDE_DIRS}
)

# link against the boost libraries
target_link_libraries( third_party_include
    PRIVATE
    ${Boost_SYSTEM_LIBRARY}
    ${Boost_FILESYSTEM_LIBRARY}
)

cmake .. -DCMAKE_C_COMPILER=clang-3.6 -DCMAKE_CXX_COMPILER=clang++-3.6 通过在cmake时加-flag更换编译器或连接器

• CMAKE_C_COMPILER - The program used to compile c code.

• CMAKE_CXX_COMPILER - The program used to compile c++ code.

• CMAKE_LINKER - The program used to link your binary.

cmake .. -G Ninja 生成别的生成器可用的生成文件，如Ninja。可用cmake -help最后查看支持的生成器。

set (CMAKE_CXX_STANDARD 11) 设置成c++11标准

target_compile_features(hello_cpp11 PUBLIC cxx_auto_type) 或增加特定特征如auto类型