如何在CMake中链接SDL2？

Question

我正在尝试在 ubuntu 上使用 sdl 。根据此说明（https://gist.github.com/BoredBored/3187339a99f7786c25075d4d9c80fad5）我安装了sdl2，sdl图像和sdl混合器。现在我必须在构建时将它们链接起来。下面的示例我应该如何做。

g++ myProgram.cpp -o myProgram `sdl2-config --cflags --libs` -lSDL2 -lSDL2_mixer -lSDL2_image -lSDL2_ttf

我正在使用 Cmake，但我不知道如何链接它们......

下面的代码只是为了测试 sdl 是否工作而完成。

//MAIN
#include <iostream>
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_mixer.h>
#include <SDL2/SDL_ttf.h>

int main(int argc, char*args[])
{
 SDL_Init(SDL_INIT_EVERYTHING);
}

下面的 CMakeList

# Set the minimum version of CMake that can be used
# To find the cmake version run
# $ cmake --version
cmake_minimum_required(VERSION 3.5)

# Set the project name
project (sdl)

# Create a sources variable with a link to all cpp files to compile
set(SOURCES
    src/main.cpp
)

# Add an executable with the above sources
add_executable(${PROJECT_NAME} ${SOURCES})

# Set the directories that should be included in the build command for this target
# when running g++ these will be included as -I/directory/path/
target_include_directories(sdl
    PRIVATE 
        ${PROJECT_SOURCE_DIR}/inc
)

我如何在 Cmake 中链接它们？谢谢你的时间。

Answer 1

要在cmake中链接库（共享/静态），您可以使用target_link_libraries命令：

target_link_libraries(<target> ... <item>... ...)

根据文档：

<target>add_executable()必须是由诸如或之类的命令创建的add_library()

因此，首先我们需要找到 SDL 库，为此我们将使用以下命令：

find_package(SDL2 REQUIRED)

要使其包含目录可供您使用，请使用以下命令：

include_directories(${SDL2_INCLUDE_DIRS})

最后要链接 SDL2，您需要执行以下操作：

target_link_libraries(${PROJECT_NAME} ${SDL2_LIBRARIES})

或者：​

target_link_libraries(${PROJECT_NAME} PRIVATE SDL2::SDL2)

PRIVATE, 表示在其实现中${PROJECT_NAME}使用SDL2，但SDL2不在${PROJECT_NAME}的公共 API 的任何部分中使用。更多这里

这${PROJECT_NAME}是<target>，后面的所有内容都是库的名称。

最后结果

# Set the minimum version of CMake that can be used
# To find the cmake version run
# $ cmake --version
cmake_minimum_required(VERSION 3.5)

# Set the project name
project (sdl)

find_package(SDL2 REQUIRED)

# Create a sources variable with a link to all cpp files to compile
set(SOURCES
    src/main.cpp
)

# Add an executable with the above sources
add_executable(${PROJECT_NAME} ${SOURCES})

target_link_libraries(sdl ${SDL2_LIBRARIES})

# Set the directories that should be included in the build command for this target
include_directories(SDL2Test ${SDL2_INCLUDE_DIRS})

参考文献：

1. https://cmake.org/cmake/help/latest/command
   
2. https://cmake.org/pipermail/cmake/2016-May/063400.html