The following example illustrates a portion of a bankapp application server that subscribes to BANK_TLR_.* events, which includes the BANK_TLR_WITHDRAWAL event shown in the previous example, as well as any other event names beginning with BANK_TLR_. When a matching event is posted, the application notifies the subscriber via a call to a service named WATCHDOG.

Listing Subscribing to an Event with tpsubscribe( )

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/* Event Subscription handles */
static long sub_ev_largeamt = 0L ;
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/* Preset default for option 'w' - watchdog threshold */
(void)strcpy (amt_expr, "AMOUNT > 10000.00") ;
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/*
 * Subscribe to the events generated
 * when a "large" amount is transacted.
 */
evctl.flags = TPEVSERVICE ;
(void)strcpy (evctl.name1, "WATCHDOG") ;
/* Subscribe */
sub_ev_largeamt = tpsubscribe ("BANK_TLR_.*",amt_expr,&evctl,TPSIGRSTRT) ;
if (sub_ev_largeamt == -1L) {
     (void)userlog ("ERROR: tpsubscribe for event BANK_TLR_.* failed: %s",
     tpstrerror(tperrno)) ;
     return -1 ;
}
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{
/* Unsubscribe to the subscribed events */
if (tpunsubscribe (sub_ev_largeamt, TPSIGRSTRT) == -1)
    (void)userlog ("ERROR: tpunsubscribe to event BANK_TLR_.* failed: %s",
    tpstrerror(tperrno)) ;
    return ;
}
/*
 * Service called when a BANK_TLR_.* event is posted.
 */
void
#if defined(__STDC__) || defined(__cplusplus)
WATCHDOG(TPSVCINFO *transb)
#else
WATCHDOG(transb)
TPSVCINFO *transb;
#endif
{
FBFR *transf; /* fielded buffer of decoded message */
/* Set pointr to TPSVCINFO data buffer */
transf = (FBFR *)transb->data;
/* Print the log entry to stdout */
(void)fprintf (stdout, "%20s|%28s|%8ld|%10.2f\n",
Fvals (transf, EVENT_NAME, 0),
Fvals (transf, EVENT_TIME, 0),
Fvall (transf, ACCOUNT_ID, 0),
*( (float *)CFfind (transf, AMOUNT, 0, NULL, FLD_FLOAT)) );
/* No data must be returned by the event subscriber's svc routine */
tpreturn(TPSUCCESS, 0,NULL, 0L, 0);
}