C语言中的SDL库有啥用？

 Simple DirectMedia Layer （SDL） is a cross-platform development library designed to provide low level access to audio（声音）, keyboard（键盘）, mouse（鼠标）, joystick（操纵杆）, and graphics（图形） hardware via OpenGL and Direct3D. It is used by video playback software, emulators, and popular games including Valve's award winning catalog and many Humble Bundle games.

来源：https://wiki.libsdl.org/Introduction