cmake编写模板

cmake 输出相关信息

message(STATUS "CMake version: ${CMAKE_VERSION}")
message(STATUS "CMake C compiler: ${CMAKE_C_COMPILER}")
message(STATUS "CMake CXX compiler: ${CMAKE_CXX_COMPILER}")
message(STATUS "Build directory: ${PROJECT_BINARY_DIR}")
message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")

判断是否被当作subproject

# Determine if is built as a subproject (using add_subdirectory)
# or if it is the master project.
if (NOT DEFINED XXX_MASTER_PROJECT)
  set(XXX_MASTER_PROJECT OFF)
  if (CMAKE_CURRENT_SOURCE_DIR STREQUAL CMAKE_SOURCE_DIR)
    set(XXX_MASTER_PROJECT ON)
  endif ()
  message(STATUS "Is build as a master project: ${XXX_MASTER_PROJECT}")
endif ()

生成compile_commands.json以供clangd使用
windows下需要使用Ninja，如果使用vscode则在设置里把cmake.generator设置为Ninja
```
# generate compile_commands.json
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
```

cmake设置rpath，unix下搜索同目录下的so文件

set(CMAKE_SKIP_BUILD_RPATH  FALSE) # 加入rpath
set(CMAKE_BUILD_WITH_INSTALL_RPATH TRUE) # 表示编译的时候是否使用CMAKE_INSTALL_RPATH作为rpath路径
set(CMAKE_INSTALL_RPATH "\${ORIGIN}") # 设置rpath安装时的路径，${ORIGIN}代表运行时当前目录

参考How to set rpath origin in cmake?

cmake设置输出目录，解决windows下命令行生成目录不正确但是IDE生成目录正确的问题 一定要放在project命令后面

set(XXX_OUTPUT_DIR ${PROJECT_BINARY_DIR}/bin)
set(XXX_OUTPUT_LIB_DIR ${PROJECT_BINARY_DIR}/lib)
set(XXX_OUTPUT_PDB_DIR ${PROJECT_BINARY_DIR}/pdb)
set(XXX_PLUGINS_OUTPUT_DIR ${XXX_OUTPUT_DIR}/plugins)
# do not set cmake internal variables in functions(not work...)
# difference between windows and linux, see https://cmake.org/cmake/help/latest/manual/cmake-buildsystem.7.html#runtime-output-artifacts
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${XXX_OUTPUT_DIR})
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${XXX_OUTPUT_DIR})
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${XXX_OUTPUT_LIB_DIR})
set(CMAKE_PDB_OUTPUT_DIRECTORY ${XXX_OUTPUT_PDB_DIR})
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY_${CMAKE_BUILD_TYPE} ${XXX_OUTPUT_DIR})
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY_${CMAKE_BUILD_TYPE} ${XXX_OUTPUT_DIR})
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY_${CMAKE_BUILD_TYPE} ${XXX_OUTPUT_LIB_DIR})
set(CMAKE_PDB_OUTPUT_DIRECTORY_${CMAKE_BUILD_TYPE} ${XXX_OUTPUT_PDB_DIR})

cmake开启fPIC

if (NOT DEFINED CMAKE_POSITION_INDEPENDENT_CODE)
    # Otherwise we can't link .so libs with .a libs
    set(CMAKE_POSITION_INDEPENDENT_CODE ON)
endif()

cmake统一符号可见性，默认隐藏

if (XXX_MASTER_PROJECT AND NOT DEFINED CMAKE_CXX_VISIBILITY_PRESET)
    set(CMAKE_CXX_VISIBILITY_PRESET hidden CACHE STRING "Preset for the export of private symbols")
    set_property(CACHE CMAKE_CXX_VISIBILITY_PRESET PROPERTY STRINGS hidden default)
endif ()

if (XXX_MASTER_PROJECT AND NOT DEFINED CMAKE_VISIBILITY_INLINES_HIDDEN)
    set(CMAKE_VISIBILITY_INLINES_HIDDEN ON CACHE BOOL "Whether to add a compile flag to hide symbols of inline functions")
endif ()

集成vcpkg toolchain

if(DEFINED ENV{VCPKG_ROOT} AND NOT DEFINED CMAKE_TOOLCHAIN_FILE)
    message(STATUS "VCPKG_ROOT: $ENV{VCPKG_ROOT}")
    set(CMAKE_TOOLCHAIN_FILE "$ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake" CACHE STRING "")
endif()

集成vcpkg manifest 一定要放在project命令之前

if (XXX_RUN_TEST)
    list(APPEND VCPKG_MANIFEST_FEATURES "tests")
endif()
if (XXX_BUILD_EXAMPLES)
    list(APPEND VCPKG_MANIFEST_FEATURES "examples")
endif()
if (XXX_BUILD_BENCHMARKS)
    list(APPEND VCPKG_MANIFEST_FEATURES "benchmarks")
endif()

ctest集成gtest

enable_testing()
file(GLOB_RECURSE source CONFIGURE_DEPENDS *.h *.cpp)
find_package(GTest CONFIG REQUIRED)
add_executable(test_main ${source})
target_link_libraries(test_main PRIVATE GTest::gtest)

include(GoogleTest)
gtest_discover_tests(test_main WORKING_DIRECTORY ${XXX_OUTPUT_DIR})

cmake 拷贝文件（如dll、exe等）到指定目录

set(DLL_PATH ******)
set(OUTPUT_DIR ******)
add_custom_command(TARGET XXX POST_BUILD
    COMMAND ${CMAKE_COMMAND} -E copy_if_different
    ${DLL_PATH}
    ${OUTPUT_DIR}
    COMMENT "Copying DLL to output directory"
)