ttp://msdn.microsoft.com/library/default.asp?url=/library/en-us/multimed/htm/_win32_timeproc.asp
>Applications should not call any system-defined functions from inside a callback function,
>except for PostMessage, timeGetSystemTime, timeGetTime, timeSetEvent, timeKillEvent,
>midiOutShortMsg, midiOutLongMsg, and OutputDebugString.