Posting Events


	Corporate Info \| News \| Solutions \| Products \| Partners \| Services \| Events \| Download \| How To Buy
	http://www.oracle.com/technology/documentation/index.html \| Site Map \| Search \| PDF Files \| Contact \| Glossary

Tuxedo Doc Home \| Programming \| Topic List \| Previous \| Next \| Contents

Programming a BEA Tuxedo Application Using C

Posting Events

The tppost(3c) function enables a BEA Tuxedo client or server to post an event.

Use the following signature to call the tppost() function.

tppost(char *eventname, char *data, long len, long flags)

The following table describes the arguments to the tppost() function.

tppost( ) Function Arguments

Argument
Description

eventname

Pointer to an event name containing up to 31 characters plus NULL. The first character cannot be a dot (".") because the dot is reserved as the first character in names of BEA Tuxedo system-defined events. When defining event names, keep in mind that subscribers can use wild card capabilities to subscribe to multiple events with a single function call. Using the same prefix for a category of related event names can be helpful.

data

Pointer to a buffer previously allocated using the tpalloc() function.

len

Size of data buffer that should be posted with the event. If data points to a buffer of a type that does not require a length to be specified (for example, an FML fielded buffer) or if you set it to NULL, the len argument is ignored and the event is posted with no data.

flags

Flag options. For more information on available flag options, refer to tppost(3c) in the BEA Tuxedo C Function Reference.

Argument	Description
eventname	Pointer to an event name containing up to 31 characters plus NULL. The first character cannot be a dot (".") because the dot is reserved as the first character in names of BEA Tuxedo system-defined events. When defining event names, keep in mind that subscribers can use wild card capabilities to subscribe to multiple events with a single function call. Using the same prefix for a category of related event names can be helpful.
data	Pointer to a buffer previously allocated using the tpalloc() function.
len	Size of data buffer that should be posted with the event. If data points to a buffer of a type that does not require a length to be specified (for example, an FML fielded buffer) or if you set it to NULL, the len argument is ignored and the event is posted with no data.
flags	Flag options. For more information on available flag options, refer to tppost(3c) in the BEA Tuxedo C Function Reference.

The following example illustrates an event posting taken from the BEA Tuxedo system sample application bankapp. This example is part of the WITHDRAWAL service. One of the functions of the WITHDRAWAL service is checking for withdrawals greater than $10,000 and posting an event called BANK_TLR_WITHDRAWAL.

Posting an Event with tppost( )

.
.
.
/* Event logic related */
static float evt_thresh = 10000.00 ; /* default for event threshold */
static char  emsg[200] ;  /* used by event posting logic */
.
.
.
/* Post a BANK_TLR_WITHDRAWAL event ? */
if (amt < evt_thresh) {
     /* no event to post */
     tpreturn(TPSUCCESS, 0,transb->data , 0L, 0);
}
/* prepare to post the event */
if ((Fchg (transf, EVENT_NAME, 0, "BANK_TLR_WITHDRAWAL", (FLDLEN)0) == -1) ||
(Fchg (transf, EVENT_TIME, 0, gettime(), (FLDLEN)0) == -1) ||
(Fchg (transf, AMOUNT, 0, (char *)&amt, (FLDLEN)0) == -1)) {
     (void)sprintf (emsg, "Fchg failed for event fields: %s",
     Fstrerror(Ferror)) ;
}
/* post the event */
else if (tppost ("BANK_TLR_WITHDRAWAL", /* event name */
(char *)transf, /* data */
0L,   /* len */
TPNOTRAN | TPSIGRSTRT) == -1) {
/* If event broker is not reachable, ignore the error */
     if (tperrno != TPENOENT)
     (void)sprintf (emsg, "tppost failed: %s", tpstrerror (tperrno));
}

This example simply posts the event to the EventBroker to indicate a noteworthy occurrence in the application. Subscription to the event by interested clients, who can then take action as required, is done independently.