IStreamSample::Update (Compact 2013)
3/26/2014
This method performs a synchronous or an asynchronous update on the current sample.
Syntax
HRESULT Update(
DWORD dwFlags,
HANDLE hEvent,
PAPCFUNC pfnAPC,
DWORD dwAPCData
);
Parameters
dwFlags
[in] Flag that specifies whether the update is synchronous or asynchronous.The SSUPDATE_ASYNC flag specifies an asynchronous update, which you can set if both hEvent and pfnAPC are NULL.
Use SSUPDATE_CONTINUOUS to continuously update the sample until you call the IStreamSample::CompletionStatus method.
- hEvent
[in] Handle to an event that this method will trigger when the update is complete.
- pfnAPC
[in] Pointer to a Win32 asynchronous procedure call (APC) function that this method will call after it completes the sample update.
- dwAPCData
[in] Value that this method passes to the function specified by the pfnAPC parameter.
Return Value
Returns one of the following values.
Value |
Description |
|---|---|
E_ABORT |
The update aborted. |
E_INVALIDARG |
One of the parameters is invalid. |
E_POINTER |
One of the parameters is invalid. |
MS_E_BUSY |
This sample already has a pending update. |
MS_S_ENDOFSTREAM |
Reached the end of the stream; the sample was not updated. |
MS_S_PENDING |
The asynchronous update is pending. |
S_OK |
Success. |
Remarks
This method can be used to perform a synchronous or asynchronous update of a sample.
If hEvent and pfnAPC are NULL the update is synchronous unless the SSUPDATE_ASYNC or SSUPDATE_CONTINUOUS flag is specified.
When a synchronous update returns, the result of the function contains the I/O completion status.
You cannot specify values for both hEvent and pfnAPC; the method will fail.
Asynchronous updates might complete before the update returns; in that case, the return value is S_OK.
If you specify an event and the update returns S_OK, this method sets the event on return.
If you specify an APC function and the update returns S_OK, the APC is not queued and the function is not called.
Asynchronous updates that do not complete prior to returning return a value of MS_S_PENDING.
Applications that create multiple streams must read from each of them to avoid having their data blocked.
Requirements
Header |
dshow.h |
Library |
Strmiids.lib |