SDL多線程
SDL線程創建: SDL_CreateThread;
SDL 線程等待: SDL_WaitThread;
SDL 互斥鎖: SDL_CreateMutex / SDL_DestroyMutex;
SDL 鎖定互斥: SDL_LockMutex / SDL_UnlockMutex;
SDL條件變量(信號量): SDL_CreateCond / SDL_DestroyCond;
SDL條件變量(信號量)等待/通知: SDL_CondWait / SDL_CondSignal;
SDL_CondWait暫時釋放擁有的鎖,並進入睡眠狀態; 在別的線程中調用SDL_CondSignal後,SDL_CondWait喚醒,等到別的線程將鎖釋放後,SDL_CondWait所在線程重新擁有鎖,可以繼續往下執行;