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timeBeginPeriod

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The timeBeginPeriod function requests a minimum resolution for periodic timers.

MMRESULT timeBeginPeriod(
  UINT uPeriod  
);

Parameters

uPeriod

Minimum timer resolution, in milliseconds, for the application or device driver. A lower value specifies a higher (more accurate) resolution.

Return Values

Returns TIMERR_NOERROR if successful or TIMERR_NOCANDO if the resolution specified in uPeriod is out of range.

Remarks

Call this function immediately before using timer services, and call the timeEndPeriod function immediately after you are finished using the timer services.

You must match each call to timeBeginPeriod with a call to timeEndPeriod, specifying the same minimum resolution in both calls. An application can make multiple timeBeginPeriod calls as long as each call is matched with a call to timeEndPeriod.

This function affects a global Windows setting. Windows uses the lowest value (that is, highest resolution) requested by any process. Setting a higher resolution can improve the accuracy of time-out intervals in wait functions. However, it can also reduce overall system performance, because the thread scheduler switches tasks more often. High resolutions can also prevent the CPU power management system from entering power-saving modes. Setting a higher resolution does not improve the accuracy of the high-resolution performance counter.

Requirements

**  Windows NT/2000/XP:** Included in Windows NT 3.1 and later.
**  Windows 95/98/Me:** Included in Windows 95 and later.
**  Header:** Declared in Mmsystem.h; include Windows.h.
**  Library:** Use Winmm.lib.

See Also

Multimedia Timers, Multimedia Timer Functions, timeEndPeriod