CMake target_include_directories:我使用PUBLIC, PRIVATE或INTERFAC

Question

我有一个CMake-libraryadd_library(helpers helpers.h)，我想通过target_include_directories包括源文件。然后我必须在参数PRIVATE,PUBLIC和INTERFACE之间进行选择。

有什么区别?

Answer 1

1. PRIVATE: include只能被helper库自己使用。
2. PUBLIC:包含可以被helper库本身和任何使用helper库的目标使用，例如通过target_link_libraries(MainApplication PUBLIC libhelpers)。
3. INTERFACE:包含不能被helper库使用，只能被使用helper库的目标使用。

这个<</ol>strong>示例说明可能的导入。结构:

│   CMakeLists.txt
│   helper.cpp
│   main.cpp
│
├───details_interface
│       details_interface.cpp
│
├───details_private
│       details_private.cpp
│
└───details_public
details_public.cpp

CMakeLists.txt:

cmake_minimum_required(VERSION 3.1)
set(CMAKE_CXX_STANDARD 17)
project(cmake_experiment)
add_executable(cmake_experiment main.cpp)
target_link_libraries(cmake_experiment libhelper)
add_library(libhelper helper.cpp)
target_include_directories(libhelper
INTERFACE details_interface
PUBLIC details_public
PRIVATE details_private)

main.cpp:

#include <iostream>
#include "details_public.cpp"
#include "details_interface.cpp"
// fatal error: details_private.cpp: No such file or directory:
// #include "details_private.cpp"
int main() {
std::cout << "Hello, World!" << std::endl;
return 0;
}

helper.cpp:

#include "details_public.cpp"
#include "details_private.cpp"
// fatal error: details_interface.cpp: No such file or directory:
// #include "details_interface.cpp"