viDiscardEvents
Purpose
Discards event occurrences for specified event types and mechanisms in a session.
C Syntax
ViStatus viDiscardEvents(ViSession vi, ViEventType eventType, ViUInt16 mechanism)
Visual Basic Syntax
viDiscardEvents&(ByVal vi&, ByVal eventType&, ByVal mechanism%)
Resource Classes
All I/O session types
Parameters
| Name | Direction | Description |
|---|---|---|
|
vi |
IN |
Unique logical identifier to a session. |
|
eventType |
IN |
Logical event identifier. |
|
mechanism |
IN |
Specifies the mechanisms for which the events are to be discarded. The VI_QUEUE (1) value is specified for the queuing mechanism and the VI_SUSPEND_HNDLR (4) value is specified for the pending events in the callback mechanism. It is possible to specify both mechanisms simultaneously by specifying VI_ALL_MECH (FFFFh). |
Return Values
| Completion Codes | Description |
|---|---|
|
VI_SUCCESS |
Event queue flushed successfully. |
|
VI_SUCCESS_QUEUE_EMPTY |
Operation completed successfully, but queue was already empty. |
| Error Codes | Description |
|---|---|
|
VI_ERROR_INV_OBJECT |
The given session reference is invalid. |
|
VI_ERROR_INV_EVENT |
Specified eventType is not supported by the resource. |
|
VI_ERROR_INV_MECH |
Invalid mechanism specified. |
Description
The viDiscardEvents() operation discards all pending occurrences of the specified event types and mechanisms from the specified session. Specifying VI_ALL_ENABLED_EVENTS for the eventType parameter discards events of every type that is enabled for the given session. The information about all the event occurrences which have not yet been handled is discarded. This operation is useful to remove event occurrences that an application no longer needs. The discarded event occurrences are not available to a session at a later time. This operation does not apply to event contexts that have already been delivered to the application.
Related Topics