procedure SDL_DestroySemaphore( sem : PSDL_sem );
SDL_DestroySemaphore destroys the semaphore
pointed to by sem that was created by
SDL_CreateSemaphore. It is not safe to destroy a semaphore if there
are threads currently blocked waiting on it.
if ( my_sem <> nil ) thenbegin SDL_DestroySemaphore( my_sem ); my_sem := nil;end;