simple direct layer(sdl) 和 symbian

   sdl是个跨平台的多媒体开源库，可用来播放视频图像。 symbian版的sdl地址是: http://koti.mbnet.fi/mertama/sdl.html, 作者markus是个热心的牛人，本人得过他不少指教。

    symbian不鼓励使用多线程，但有些多媒体的复杂应用很难用活动对象来解决，所以symbian为多线程设置了Rthread类。在多线程里调用使用SDL得注意以下几点：

 

In general, you must be very aware of concurrency and data integrity issues when writing multi-threaded programs. Some good guidelines include:

• Don't call SDL video/event functions from separate threads(很重要，sdl_video里的函数比如SDL_SetVideoMode和SDL_DisplayYUVOverlay都必须放在主线程里，而不能新建个线程）

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• Don't use any library functions in separate threads

• Don't perform any memory management in separate threads

• Lock global variables which may be accessed by multiple threads

• Never terminate threads, always set a flag and wait for them to quit

• Think very carefully about all possible ways your code may interact