CMake target_include_directories 相对于父目录？

Question

如何将 lib0 路径添加到 lib1 以便从 header1.h 我可以 #include <header0.h>？

|   CMakeLists.txt
+---lib0
|       CMakeLists.txt
|       header0.c
|       header0.h
+---lib1
|       CMakeLists.txt
|       header1.c
|       header1.h
\---main
        CMakeLists.txt
        main.c

CMakeLists.txt

cmake_minimum_required(VERSION 3.19)
project(c_multilib C)

foreach (sub "lib0" "lib1" "main")
    add_subdirectory("${sub}")
endforeach ()

lib0/CMakeLists.txt

add_library(lib0 "header0.h" "header0.c")

set_target_properties(lib0 PROPERTIES LINKER_LANGUAGE C)

include(GenerateExportHeader)
set(_generated_export_header "${CMAKE_CURRENT_SOURCE_DIR}/lib0_export.h")
generate_export_header(lib0 EXPORT_FILE_NAME "${_generated_export_header}")

target_include_directories(lib0
        INTERFACE
        "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>"
        "$<INSTALL_INTERFACE:include>"
)

install(FILES "header0.h" "${_generated_export_header}" DESTINATION "include")

lib0/header0.h

#ifndef C_MULTILIB_HEADER0_H
#define C_MULTILIB_HEADER0_H

#include "lib0_export.h"

int LIB0_EXPORT sum(int, int);

#endif /* C_MULTILIB_HEADER0_H */

lib0/header0.c

#include "header0.h"

int sum(int a, int b) {return a+b;}

lib1/CMakeLists.txt

add_library(lib1 "header1.h" "header1.c")

set_target_properties(lib1 PROPERTIES LINKER_LANGUAGE C)

include(GenerateExportHeader)
set(_generated_export_header "${CMAKE_CURRENT_SOURCE_DIR}/lib1_export.h")
generate_export_header(lib1 EXPORT_FILE_NAME "${_generated_export_header}")

target_include_directories(lib1
        INTERFACE
        "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>"
        "$<BUILD_INTERFACE:${${PROJECT_NAME}_SOURCE_DIR}/lib0>"
        "$<INSTALL_INTERFACE:include>"
)

install(FILES "header1.h" "${_generated_export_header}" DESTINATION "include")

lib1/header1.h

#ifndef C_MULTILIB_HEADER1_H
#define C_MULTILIB_HEADER1_H

#include <header0.h>
#include "lib1_export.h"

int LIB1_EXPORT add1(int);

#endif /* C_MULTILIB_HEADER1_H */

lib1/header1.c

#include <header1.h>

int add1(int a) {return sum(a, 1);}

main/CMakeLists.txt

add_executable("main" "main.c")

target_link_libraries("main" "lib0" "lib1")
target_include_directories(
        "main"
        INTERFACE
        "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>"
        "$<BUILD_INTERFACE:${${PROJECT_NAME}_SOURCE_DIR}/lib0>"
        "$<BUILD_INTERFACE:${${PROJECT_NAME}_SOURCE_DIR}/lib1>"
        "$<INSTALL_INTERFACE:include>"
)

main/main.c

#include <header0.h>
#include <header1.h>
#include <stdio.h>
#include <stdlib.h>

int main(void) {
    printf("sum(1,5) =\t%d\n"
                   "add1(5) =\t%d\n", sum(1,5), add1(6));
    return EXIT_SUCCESS;
}

尝试次数：

# lib1/CMakeLists.txt

target_include_directories(
    lib1
    INTERFACE
    "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>"
    #"$<BUILD_INTERFACE:lib0>"
    #"$<BUILD_INTERFACE:../../lib0>"
    #"$<BUILD_INTERFACE:${${PROJECT_NAME}_SOURCE_DIR}/src/lib0>"
    "$<INSTALL_INTERFACE:include>"
)

install(FILES "header1.h" DESTINATION "include")

错误范围为：

fatal error C1083: Cannot open include file: 'header0.h': No such file or directory

至：

Target contains relative path in its INTERFACE_INCLUDE_DIRECTORIES

也get_target_property(LIB0_INCLUDES "lib0" INCLUDE_DIRECTORIES)给了：

get_target_property() called with non-existent target "lib0".

Answer 1

src/lib0/CMakeLists.txt 应该看起来像这样

add_library(lib0 INTERFACE)
target_include_directories(lib0 INTERFACE ${CMAKE_CURRENT_LIST_DIR})

单词INTERFACE告诉Cmake没有什么可编译的。

src/lib1/CMakeLists.txt 应该看起来像这样

add_library(lib1 INTERFACE)
target_include_directories(lib1 INTERFACE ${CMAKE_CURRENT_LIST_DIR})
target_link_libraries(lib1 INTERFACE lib0)

src/CMakeLists.txt 应该类似于

add_subdirectory(lib0)
add_subdirectory(lib1)
# Assuming that your src target is called my_proj: 
target_link_libraries(my_proj PRIVATE lib0 lib1)

编辑：

如果您将所有包含项从 lib1_export... 更改为 header1 并修改以下 3 个 CMakeLists.txt 文件，我可以确认您提供的代码可以编译：

lib0/CMakeLists.txt:

add_library(lib0 header0.c)
target_include_directories(lib0 PUBLIC ${CMAKE_CURRENT_LIST_DIR})

lib1/CMakeLists.txt:

add_library(lib1 header1.c)
target_include_directories(lib1 PUBLIC ${CMAKE_CURRENT_LIST_DIR})
target_link_libraries(lib1 PUBLIC lib0)

main/CMakeLists.txt:

add_executable(main main.c)
target_link_libraries(main PRIVATE lib0 lib1)

我不清楚你试图用生成器表达式（尖括号）实现什么。如果您解释了您想要完成的目标，那么我们可以建议适当的修复。