while (true)
    {
        SDL_PumpEvents();
        if (SDL_PeepEvents(&sdlEvent, 1, SDL_GETEVENT, SDL_FIRSTEVENT, SDL_LASTEVENT) == 0)
            break;

        if (sdlEvent.type == SDL_KEYDOWN || sdlEvent.type == SDL_KEYUP)
        {
            SDL_Scancode scancode = sdlEvent.key.keysym.scancode;
            // какой-то код
        }
    }