运行自定义目标

你还可以创建要在执行特定任务时运行的自定义目标。这些通常是你运行以执行不同操作的可执行文件。可能特别有用的是运行 Doxygen 为你的项目生成文档。为此，你可以在 CMakeLists.txt 中执行以下操作（为简单起见，我们将继续我们的 Qt5 项目示例）：

cmake_minimum_required(VERSION 3.0)
project(MyQtProj LANGUAGES C CXX)
find_package(Qt5 COMPONENTS Core Gui Widgets)
#...set up your project

add_executable(MyQtProj ${PROJ_SOURCES} ${PROJ_HEADERS})
    
add_custom_command(TARGET MyQtProj POST_BUILD
    COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:Qt5::Core> $<TARGET_FILE_DIR:MyQtProj>
    COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:Qt5::Gui> $<TARGET_FILE_DIR:MyQtProj>
    COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:Qt5::Widgets> $<TARGET_FILE_DIR:MyQtProj>
    )

#Add target to build documents from visual studio.
set(DOXYGEN_INPUT ${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile)
#set the output directory of the documentation
set(DOXYGEN_OUTPUT_DIR ${CMAKE_CURRENT_SOURCE_DIR}/docs)
# sanity check...
message("Doxygen Output ${DOXYGEN_OUTPUT_DIR}")
find_package(Doxygen)

if(DOXYGEN_FOUND)
    # create the output directory where the documentation will live
    file(MAKE_DIRECTORY ${DOXYGEN_OUTPUT_DIR})
    # configure our Doxygen configuration file. This will be the input to the doxygen
    # executable
    configure_file(${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile.in
    ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile @ONLY)

# now add the custom target. This will create a build target called 'DOCUMENTATION' 
# in your project
ADD_CUSTOM_TARGET(DOCUMENTATION
  COMMAND ${CMAKE_COMMAND} -E echo_append "Building API Documentation..."
  COMMAND ${CMAKE_COMMAND} -E make_directory ${DOXYGEN_OUTPUT_DIR}
  COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile
    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
  COMMAND ${CMAKE_COMMAND} -E echo "Done."
  WORKING_DIRECTORY ${DOXYGEN_OUTPUT_DIR})

endif(DOXYGEN_FOUND)

现在，当我们创建我们的解决方案时（再次假设你使用的是 Visual Studio），你将拥有一个名为 DOCUMENTATION 的构建目标，你可以构建该目标以重新生成项目的文档。