IReferenceClock::AdvisePeriodic
| Microsoft DirectShow 9.0 |
IReferenceClock::AdvisePeriodic
The AdvisePeriodic method creates a periodic advise request.
Syntax
HRESULT AdvisePeriodic( REFERENCE_TIME rtStartTime, REFERENCE_TIME rtPeriodTime, HSEMAPHORE hSemaphore, DWORD_PTR *pdwAdviseCookie );
Parameters
rtStartTime
[in] Time of the first notification, in 100-nanosecond units. Must be greater than zero and less than MAX_TIME.
rtPeriodTime
[in] Time between notifications, in 100-nanosecond units. Must be greater than zero.
hSemaphore
[in] Handle to a semaphore, created by the caller.
pdwAdviseCookie
[out] Pointer to a variable that receives an identifier for the advise request.
Return Value
Returns an HRESULT value. Possible values include the following.
| Return code | Description |
| S_OK | Success. |
| E_INVALIDARG | Invalid time values. |
| E_OUTOFMEMORY | Failure. |
| E_POINTER | NULL pointer argument. |
Remarks
At each notification time, the clock releases the semaphore specified in the hSemaphore parameter. When no further notifications are required, call IReferenceClock::Unadvise and pass the pdwAdviseToken value returned from this call.
The following code example creates an advise request that signals five seconds from the time it is created, and again every second thereafter:
IReferenceClock *pRefClock = NULL;
// Get an IReferenceClock pointer (not shown).
DWORD dwAdviseToken;
HANDLE hSemaphore = CreateSemaphore(NULL, 0, 0x7FFFFFFF, NULL);
REFERENCE_TIME rtPeriodTime = 10000000; // A one-second interval
REFERENCE_TIME rtNow;
pRefClock->GetTime(&rtNow);
pRefClock->AdvisePeriodic(rtNow + (5 * rtPeriodTime),
rtPeriodTime,
hSemaphore,
&dwAdviseToken);
...
pRefClock->Unadvise(dwAdviseToken);
Requirements
Header: Declared in Strmif.h; include Dshow.h.
Library: Use Strmiids.lib.
See Also