/* Handle for the trigger group of events. */
AMXID amxidTrigger;

/* Constants for use in the group. */
#define TRIGGER_MASK  0x0001
#define TRIGGER_SET   0x0001
#define TRIGGER_RESET 0x0000

void main (void)
{
    .
    .
    .
    /* Create an event group with 
       the trigger and keyboard events reset */
    ajevcre (&amxidTrigger, 0, "EVTR");
    .
    .
    .
}

void interrupt vTriggerISR (void)
{
    /* The user pulled the trigger. Set the event. */
    ajevsig (amxidTrigger, TRIGGER_MASK, TRIGGER_SET);
}

void vScanTask (void)
{
    .
    .
    .
    while (TRUE)
    {
        /* Wait for the user to pull the trigger. */
        ajevwat (amxidTrigger, TRIGGER_MASK, TRIGGER_SET,
           WAIT_FOR_ANY, WAIT_FOREVER);
        
        /* Reset the trigger event. */
        ajevsig (amxidTrigger, TRIGGER_MASK, TRIGGER_RESET);

        !! Turn on the scanner hardware and look for a scan.
    }
}