/* evntqueu.c

   This example program illustrates enabling an event queue 

   using viWaitOnEvent. Note that you must change the address. */

#include <visa.h>

#include <stdio.h>

void main(){

   ViSession defaultRM,vi;

   ViEventType eventType;

   ViEvent eventVi;

   ViStatus err;

   ViInt16 trigId;

   /* open session to VXI device */

   viOpenDefaultRM(&defaultRM);

   viOpen(defaultRM, "VXI0::24::INSTR", VI_NULL, VI_NULL, &vi);

   /* select trigger line TTL0 */

   viSetAttribute(vi, VI_ATTR_TRIG_ID, VI_TRIG_TTL0);

   /* enable the event */

   viEnableEvent(vi, VI_EVENT_TRIG, VI_QUEUE, VI_NULL);

   /* fire trigger line, twice */

   viAssertTrigger(vi, VI_TRIG_PROT_SYNC);

   viAssertTrigger(vi, VI_TRIG_PROT_SYNC);

   /* Wait for the event to occur */

   err=viWaitOnEvent(vi, VI_EVENT_TRIG, 10000, &eventType, &eventVi);

   if(err==VI_ERROR_TMO){

      printf("Timeout Occurred! Event not received.\n");

      return;

   }

   /* print the event information */

   printf("Trigger Event Occurred!\n");

   printf("...Original Device Session = %ld\n", vi);

   /* get trigger that fired */

   viGetAttribute(eventVi, VI_ATTR_RECV_TRIG_ID, &trigId);

   printf("Trigger that fired: ");

   switch(trigId){

      case VI_TRIG_TTL0:

         printf("TTL0");

         break;

      default:

         printf("<other 0x%x>",trigId);

         break;

   }

   printf("\n");

   /* close the context before continuing */

   viClose(eventVi);

   /* get second event */

   err=viWaitOnEvent(vi, VI_EVENT_TRIG, 10000, &eventType, &eventVi);

   if(err==VI_ERROR_TMO){

      printf("Timeout Occurred! Event not received.\n");

      return;

   }

   printf("Got second event\n");

   /* close the context before continuing */

   viClose(eventVi);

   /* unenable event */

   viDisableEvent(vi, VI_EVENT_TRIG, VI_QUEUE);

   /* close the sessions */

   viClose(vi);

   viClose(defaultRM);

}