IReferenceClock::AdvisePeriodic method (strmif.h)

Artículo
10/21/2021
Tiempo de lectura: 2 minutos

The AdvisePeriodic method creates a periodic advise request.

Syntax

HRESULT AdvisePeriodic(
  [in]  REFERENCE_TIME startTime,
  [in]  REFERENCE_TIME periodTime,
  [in]  HSEMAPHORE     hSemaphore,
  [out] DWORD_PTR      *pdwAdviseCookie
);

Parameters

[in] startTime

Time of the first notification, in 100-nanosecond units. Must be greater than zero and less than MAX_TIME.

[in] periodTime

Time between notifications, in 100-nanosecond units. Must be greater than zero.

[in] hSemaphore

Handle to a semaphore, created by the caller.

[out] pdwAdviseCookie

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:

C++
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);

C++

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


Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	strmif.h (include Dshow.h)
Library	Strmiids.lib