如何在sdl中同时使用键盘的两个键

#include <SDL.h>

int main(int argc, char* argv[]) {
    // 初始化SDL库
    SDL_Init(SDL_INIT_VIDEO);

    // 创建窗口和渲染器
    SDL_Window* window = SDL_CreateWindow("SDL Keyboard", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 800, 600, SDL_WINDOW_SHOWN);
    SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, 0);

    // 事件循环
    bool quit = false;
    bool keyA = false;
    bool keyB = false;

    while (!quit) {
        SDL_Event event;
        while (SDL_PollEvent(&event)) {
            if (event.type == SDL_QUIT) {
                quit = true;
            }
            else if (event.type == SDL_KEYDOWN) {
                if (event.key.keysym.sym == SDLK_a) {
                    keyA = true;
                }
                else if (event.key.keysym.sym == SDLK_b) {
                    keyB = true;
                }
            }
            else if (event.type == SDL_KEYUP) {
                if (event.key.keysym.sym == SDLK_a) {
                    keyA = false;
                }
                else if (event.key.keysym.sym == SDLK_b) {
                    keyB = false;
                }
            }
        }

        // 判断两个键是否同时按下
        if (keyA && keyB) {
            // 两个键同时按下的处理逻辑
        }

        // 渲染窗口
        SDL_RenderClear(renderer);
        SDL_RenderPresent(renderer);
    }

    // 清理SDL库
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();

    return 0;
}