User`s guide

Programming with VISA 3
Agilent VISA User’s Guide 63
• When ready to query, use the viWaitOnEvent function to check for
queued events.
If the specified event has occurred, the event information is retrieved
and the program returns immediately. If the specified event has not
occurred, the program suspends execution until a specified event occurs
or until the specified timeout period is reached.
Example: Using the Queuing Method This example program
shows one way you can use the queuing method.
main();
ViSession vi;
ViEventType eventType;
ViEvent event;
.
.
viEnableEvent(vi, VI_EVENT_SERVICE_REQ,
VI_QUEUE, VI_NULL);
.
.
viWaitOnEvent(vi, VI_EVENT_SERVICE_REQ,
VI_TMO_INFINITE, &eventType, &event);
.
.
viClose(event);
viDisableEvent(vi, VI_EVENT_SERVICE_REQ,
VI_QUEUE);
}
Enabling Events
Before an event can be delivered, it must be enabled using the
viEnableEvent function:
viEnableEvent(vi, eventType, mechanism,
context);
These parameters are defined as follows: