Microsoft DirectX 9.0


The AsynchronousBlockOutputPin method blocks the pin. The method might return before the pin is blocked.


HRESULT AsynchronousBlockOutputPin(
    HANDLE hNotifyCallerPinBlockedEvent



Handle to an event. The event is signaled when the output pin is blocked, or if the caller cancels the block operation.

Return Value

Returns an HRESULT value. Possible values include those shown in the following table.

Value Description
S_OK Success.
VFW_E_PIN_ALREADY_BLOCKED Pin is already blocked on another thread.
VFW_E_PIN_ALREADY_BLOCKED_ON_THIS_THREAD Pin is already blocked on the calling thread.


Do not call this method from the streaming thread.

If no streaming thread is using the pin, this method immediately blocks the pin. Otherwise, it sets the pin status to "pending" and returns. When the streaming operation completes, the streaming thread calls the CDynamicOutputPin::StopUsingOutputPin method, which blocks the pin and signals the hNotifyCallerPinBlockedEvent event. To cancel a pending block, call the CDynamicOutputPin::UnblockOutputPin method.

See Also