CBaseReferenceClock::AdvisePeriodic (Compact 2013)
3/26/2014
Sets up a recurring advise with the reference clock.
Syntax
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 Value
Returns one of the following HRESULT values.
Value |
Description |
|---|---|
E_OUTOFMEMORY |
Out of memory. |
E_INVALIDARG |
Invalid argument. |
NOERROR |
No error. |
Remarks
A semaphore, rather than an event, is used to ensure that multiple notifications can be seen by the user.
Each time an amount of time specified in the PeriodTime parameter elapses, the semaphore is released.
When no further notifications are required, call CBaseReferenceClock::Unadvise and pass the pdwAdviseToken value 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 Unadvise is 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);
Requirements
Header |
dshow.h, |
Library |
ole32.lib, |