timeSetEvent function

Article
06/06/2016

The timeSetEvent function starts a specified timer event. The multimedia timer runs in its own thread. After the event is activated, it calls the specified callback function or sets or pulses the specified event object.

Note This function is obsolete. New applications should use CreateTimerQueueTimer to create a timer-queue timer.

Syntax

MMRESULT timeSetEvent(
   UINT           uDelay,
   UINT           uResolution,
   LPTIMECALLBACK lpTimeProc,
   DWORD_PTR      dwUser,
   UINT           fuEvent
);

Parameters

uDelay
Event delay, in milliseconds. If this value is not in the range of the minimum and maximum event delays supported by the timer, the function returns an error.
uResolution
Resolution of the timer event, in milliseconds. The resolution increases with smaller values; a resolution of 0 indicates periodic events should occur with the greatest possible accuracy. To reduce system overhead, however, you should use the maximum value appropriate for your application.
lpTimeProc
Pointer to a callback function that is called once upon expiration of a single event or periodically upon expiration of periodic events.

If fuEvent specifies the TIME_CALLBACK_EVENT_SET or TIME_CALLBACK_EVENT_PULSE flag, then the lpTimeProc parameter is interpreted as a handle to an event object. The event will be set or pulsed upon completion of a single event or periodically upon completion of periodic events.

For any other value of fuEvent, the lpTimeProc parameter is a pointer to a callback function of type LPTIMECALLBACK.
dwUser
User-supplied callback data.

fuEvent
Timer event type. This parameter may include one of the following values.

Value	Meaning
TIME_ONESHOT	Event occurs once, after uDelay milliseconds.
TIME_PERIODIC	Event occurs every uDelay milliseconds.

The fuEvent parameter may also include one of the following values.

Value	Meaning
TIME_CALLBACK_FUNCTION	When the timer expires, Windows calls the function pointed to by the lpTimeProc parameter. This is the default.
TIME_CALLBACK_EVENT_SET	When the timer expires, Windows calls the SetEvent function to set the event pointed to by the lpTimeProc parameter. The dwUser parameter is ignored.
TIME_CALLBACK_EVENT_PULSE	When the timer expires, Windows calls the PulseEvent function to pulse the event pointed to by the lpTimeProc parameter. The dwUser parameter is ignored.
TIME_KILL_SYNCHRONOUS	Passing this flag prevents an event from occurring after the timeKillEvent function is called.

Return value

Returns an identifier for the timer event if successful or an error otherwise. This function returns NULL if it fails and the timer event was not created. (This identifier is also passed to the callback function.)

Remarks

Each call to timeSetEvent for periodic timer events requires a corresponding call to the timeKillEvent function.

Creating an event with the TIME_KILL_SYNCHRONOUS and the TIME_CALLBACK_FUNCTION flag prevents the event from occurring after the timeKillEvent function is called.

Requirements

Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Header	TimeAPI.h (include Windows.h); Mmsystem.h on Windows Server 2008 R2, Windows 7, Windows 7, Windows Server 2008 and Windows Vista (include Windows.h)
Library	Winmm.lib
DLL	Winmm.dll

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