Header file for SDL_Overlay

问题

I plan to use both SDL_GetKeyboardState and SDL_Overlay but it seems there is a conflict.

#include <stdio.h>
#include <SDL/SDL.h>
#include <SDL2/SDL.h>

int main()
{
    const Uint8 *keystate = SDL_GetKeyboardState(NULL);
    SDL_Overlay *bmp;
    printf("hello world!");
}

Compile:

gcc -c main.cpp

---

When order of headers are:

#include <SDL/SDL.h>
#include <SDL2/SDL.h>

error: ‘SDL_GetKeyboardState’ was not declared in this scope
 const Uint8 *keystate = SDL_GetKeyboardState(NULL);
                                                  ^

or

#include <SDL2/SDL.h>
#include <SDL/SDL.h>

error: ‘SDL_Overlay’ was not declared in this scope
     SDL_Overlay *bmp;
     ^

Even adding

#include <SDL2/SDL_video.h>

does not solve the problem.

What header should I add to use SDL_Overlay?

来源：https://stackoverflow.com/questions/47391289/header-file-for-sdl-overlay