Using Sdl2 with Cmake

Using SDL2 with CMake

Don't set the path to SDL2 by hand. Use the proper find command which uses FindSDL. Should look like:

find_file(SDL2_INCLUDE_DIR NAME SDL.h HINTS SDL2)
find_library(SDL2_LIBRARY NAME SDL2)
add_executable(ChickenShooter main.cpp)
target_include_directories(ChickenShooter ${SDL2_INCLUDE_DIR})
target_link_libraries(ChickenShooter ${SDL2_LIBRARY})    

If SDL2 is not found, you have to add the path to SDL2 to CMAKE_PREFIX_PATH, that's the place where CMake looks for installed software.

If you can use Pkg-config, its use might be easier, see How to use SDL2 and SDL_image with cmake

Linking SDL2 with CMake

Thanks to Tsyvarev!
Setting the macro SDL_MAIN_HANDLED in the source file fixed the problem.

#define SDL_MAIN_HANDLED // insert this
#include <iostream>
#include "SDL.h"

int main() {
    if (SDL_Init(SDL_INIT_VIDEO) != 0){
        std::cout << "Hello world" << std::endl;
        return 1;
    }
    
        std::cout << "Hello world 2" << std::endl;

    SDL_Quit();
    return 0;
}

How to link SDL2 in CMake?

To link a library (shared/static) in cmake you can use the target_link_libraries command:

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

According to the documentation:

<target> must have been created by a command such as add_executable() or add_library()

So first of all we need to find the SDL library, for that we will use the command:

find_package(SDL2 REQUIRED)

to make it's include directories available to you, use the command:

include_directories(${SDL2_INCLUDE_DIRS})

And finally to link SDL2, you need to do:

target_link_libraries(${PROJECT_NAME} ${SDL2_LIBRARIES})

or alternatively:

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

PRIVATE, means that ${PROJECT_NAME} uses SDL2 in its implementation, but SDL2 is not used in any part of ${PROJECT_NAME}'s public API. More here

Here ${PROJECT_NAME} is the <target>, and all the rest that follow are names of libraries.

Final Result

    # 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})

What happened to FindSDL2 in CMake?

FindSDL2 has never appeared in CMake.
Following the reject reason in pull request #149, SDL2 ships with a SDL2Config.cmake, which provides a cmake package.
The documentation for find_package states that find_package(SDL2) will behave as follows:

• Look for FindSDL2.cmake, use that if it exists. (module mode)
• Otherwise, use the information in SDL2Config.cmake or sdl2-config.cmake. (config mode)

In short, make sure that your SDL2 package has installed the SDL2Config.cmake file and that is on your CMAKE_PREFIX_PATH. The documentation lists the exact paths and prefixes it looks under.

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