Question

我创建了一个仅标头的库，该库与cmake一起使用

add_library(mylib INTERFACE)

并导出目标。当我在另一个包含头文件的库（find_package(mylib REQUIRED)）的cmake文件中使用target_link_library和mylib2时，此方法很好用。

但是当我使用导出的目标和mylib2针对target_link_library进行链接时，生成的VS文件在链接库中包含mylib.lib。

当我在所有三个项目的生成文件中寻找字符串mylib.lib时，只有Visual Studio文件包含此文件，PackageConfig或PackageTargets文件中都不包含文件名。

标头库在其CMakeLists.txt中使用导出的目标

add_library(mylib INTERFACE)
target_compile_definitions(mylib INTERFACE -D_USE_MATH_DEFINES)
target_link_libraries(mylib INTERFACE somelibraries)
target_include_directories(mylib INTERFACE
        $<INSTALL_INTERFACE:include>
        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
)
configure_package_config_file(mylibConfig.cmake.in ${CMAKE_CURRENT_BINARY_DIR}/mylibConfig.cmake INSTALL_DESTINATION ${CMAKE_INSTALL_PREFIX})
install(TARGETS mylib EXPORT mylib-targets)
install(EXPORT mylib-targets FILE mylibTargets.cmake DESTINATION ${CMAKE_INSTALL_PREFIX})
install(FILES ${CMAKE_CURRENT_BINARY_DIR}/mylibConfig.cmake DESTINATION ${CMAKE_INSTALL_PREFIX})
install(DIRECTORY ./ DESTINATION include FILES_MATCHING PATTERN "*.h")

第二个库仅使用

find_package(mylib REQUIRED)
add_library(mylib2 source.cpp)
target_link_libraries(mylib2 mylib)
# some stuff to export targets, similar to the first lib

最终项目使用

add_binary(myproject source.cpp)
set(LINK_LIBRARIES mylib2)
target_link_libraries(myproject ${LINK_LIBRARIES}) # mylib2.lib is added to the project.

add_binary(myproject2 source.cpp)
target_link_libraries(myproject mylib2) # only the include paths are added.

仅当通过变量设置库时才会发生此问题。

在该过程的哪一步，cmake会将库文件名添加到链接库中？它不应该继承INTERFACE属性吗？

Answer 1

要包含库，通常必须包含头文件并链接一些目标文件。

话虽如此，如果所说的库是仅标头的，则只需执行include_directories(<library-include-folder>)就可以了。通常，您的库不应编译为.lib文件。

在您的情况下，您可能需要执行以下操作：（假设mylib仅用于标头）

find_package(mylib REQUIRED)
# Provides MYLIB_INCLUDE_DIR to include
# The line above also provides a MYLIB_LIBRARIES, which for header-only libraries should be empty

include_directories(${MYLIB_INCLUDE_DIR})
add_executable(main main.cpp)
target_link_libraries(main ${MYLIB_LIBRARIES}) # This can be onmitted since there is nothing to link

如何在cmake中要求不带二进制文件的仅标头库？

1 个答案: