在CMake项目中带有前缀的头文件

Posted 2021-05-04

我已经设置了一个CMake项目，其目录结构如下所示：

src/
--CMakeLists.txt
--libA/
----CMakeLists.txt
----foo.h
----foo.cpp
--main/
----CMakeLists.txt
----main.cpp

src/CMakeLists.txt使用add_subdirectory拉入libA和main。 libA/CMakeLists.txt使用add_library定义一个名为libA的库，它通过foo.h输出target_include_directories。如果我现在使用libA链接main中的target_link_library，我可以在foo.h中通过#include <foo.h>包含main.cpp。

问题：是否有可能为libA提供前缀的公共接口，以便我可以（并且必须）在#include <libA/foo.h>中编写main.cpp？

答案

这是一个老问题，但我遇到了完全相同的问题。我最后通过添加一个export_headers()函数来解决这个问题，该函数创建了二进制文件中标题的符号链接：

function(export_headers TARGET HEADER_SOURCE_DIR HEADER_DEST_DIR)

    # Put all headers that are in the source directory into EXPORT_HEADERS variable
    file(GLOB_RECURSE EXPORT_HEADERS CONFIGURE_DEPENDS 
        RELATIVE "${HEADER_SOURCE_DIR}" 
        "${HEADER_SOURCE_DIR}/*.h"
    )

    # For each header that will be exported
    foreach(HEADER ${EXPORT_HEADERS})

        # Get the directory portion that needs to be created        
        get_filename_component(HEADER_DIRECTORY "${HEADER}" DIRECTORY)

        # Create the directory  
        add_custom_command(TARGET ${TARGET} POST_BUILD
            COMMAND ${CMAKE_COMMAND} -E make_directory "${HEADER_DEST_DIR}/${HEADER_DIRECTORY}"
        )

        if (MSVC)

            # Make a hard link to the file
            add_custom_command(TARGET ${TARGET} POST_BUILD
                COMMAND if not exist "${HEADER_DEST_DIR}/${HEADER}" ( mklink /h "${HEADER_DEST_DIR}/${HEADER}" "${HEADER_SOURCE_DIR}/${HEADER}" ) 
            )

        else()

            # Make a symbolic link to the file
            add_custom_command(TARGET ${TARGET} POST_BUILD
                COMMAND ln -sf "${HEADER_SOURCE_DIR}/${HEADER}" "${HEADER_DEST_DIR}/${HEADER}"
            )

        endif()


    endforeach(HEADER)

endfunction()

你可以这样称呼：

add_library(libA STATIC ${LIBA_SOURCES}
export_headers(libA ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}/include/libA)
target_include_directories(libA INTERFACE ${CMAKE_CURRENT_BINARY_DIR}/include)

然后，如果你链接到libA，你将能够#include <libA/foo.h>。