TimeProc callback function

The TimeProc function callback function that is called once upon the expiration of a single event or periodically upon the expiration of periodic events.

Note  TimeProc is a placeholder for the application-defined function name.



void CALLBACK TimeProc(
   UINT  uID,
   UINT  uMsg,
   DWORD dwUser,
   DWORD dw1,
   DWORD dw2


  • uID
    Identifier of the timer event. This identifier was returned by the timeSetEvent function when the timer event was set up.

  • uMsg
    Reserved; do not use.

  • dwUser
    User instance data supplied to the dwUser parameter of timeSetEvent.

  • dw1
    Reserved; do not use.

  • dw2
    Reserved; do not use.

Return value

This function does not return a value.


Applications should not call any system-defined functions from inside a callback function, except for PostMessage, timeGetSystemTime, timeGetTime, timeSetEvent, timeKillEvent, midiOutShortMsg, midiOutLongMsg, and OutputDebugString.


Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]


Mmsystem.h (include Windows.h)

See also

Multimedia Timers

Multimedia Timer Functions