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Sets up a recurring advise with the reference clock.
HRESULT AdvisePeriodic( REFERENCE_TIME StartTime , REFERENCE_TIME PeriodTime , HSEMAPHORE hSemaphore , DWORD * pdwAdviseToken );
Parameters
- StartTime
- Start at this time.
- PeriodTime
- Time between notifications.
- hSemaphore
- Advise through a semaphore.
- pdwAdviseToken
- Advise token that identifies the link with the clock.
Return Values
Returns one of the following HRESULTvalues:
E_OUTOFMEMORY E_INVALIDARG NOERROR No error. Remarks
A semaphore is used, rather than an event, to ensure that multiple notifications can be seen by the user. Each time an amount of time specified in the PeriodTimeparameter elapses, the semaphore will be released.
When no further notifications are required, call CBaseReferenceClock::Unadviseand pass the pdwAdviseTokenvalue returned from this call.
For example, the following code extract sets up an advise link that fires its first advise five seconds from now and then signals every second until Unadviseis called. By using a semaphore with a count of 10, the clock is effectively able to cache 10 events.
HANDLE hSemaphore = CreateSemaphore(NULL, 0, 10, NULL); // Assume pRefClock is an IReferenceClock* variable. REFERENCE_TIME rtPeriodTime = 1000 * (UNITS / MILLISECONDS); // A one-second interval REFERENCE_TIME rtNow; DWORD dwAdviseToken; pRefClock->GetTime(&rtNow); pRefClock->AdvisePeriodic(rtNow+(5*rtPeriodTime), PeriodTime, hSemaphore, &dwAdviseToken);