Section 3c - C Functions

ATMI C Function Reference

tpunsubscribe(3c)

Name

tpunsubscribe()—Unsubscribes to an event.

Synopsis

#include <atmi.h> 
int tpunsubscribe(long subscription, long flags)

Description

The caller uses tpunsubscribe() to remove an event subscription or a set of event subscriptions from the BEA Tuxedo EventBroker's list of active subscriptions. subscription is an event subscription handle returned by tpsubscribe(). Setting subscription to the wildcard value, -1, directs tpunsubscribe() to unsubscribe to all non-persistent subscriptions previously made by the calling process. Non-persistent subscriptions are those made without the TPEVPERSIST bit setting in the ctl—>flags parameter of tpsubscribe(). Persistent subscriptions can be deleted only by using the handle returned by tpsubscribe().

Note that the -1 handle removes only those subscriptions made by the calling process and not any made by previous instantiations of the caller (for example, a server that dies and restarts cannot use the wildcard to unsubscribe to any subscriptions made by the original server).

The following is a list of valid flags:

TPNOBLOCK

The subscription is not removed if a blocking condition exists. If such a condition occurs, the call fails and tperrno is set to TPEBLOCK. When TPNOBLOCK is not specified and a blocking condition exists, the caller blocks until the condition subsides or a timeout occurs (either transaction or blocking timeout).

TPNOTIME

This flag signifies that the caller is willing to block indefinitely and wants to be immune to blocking timeouts. Transaction timeouts may still occur.

TPSIGRSTRT

If a signal interrupts any underlying system calls, then the interrupted system call is reissued. When TPSIGRSTRT is not specified and a signal interrupts a system call, then tpunsubscribe() fails and tperrno is set to TPGOTSIG.

In a multithreaded application, a thread in the TPINVALIDCONTEXT state is not allowed to issue a call to tpunsubscribe().

Return Values

Upon completion of tpunsubscribe(), tpurcode() contains the number of subscriptions deleted (zero or greater) from the EventBroker's list of active subscriptions. tpurcode() may contain a number greater than 1 only when the wildcard handle, -1, is used. Also, tpurcode() may contain a number greater than 0 even when tpunsubscribe() completes unsuccessfully (that is, when the wildcard handle is used, the EventBroker may have successfully removed some subscriptions before it encountered an error deleting others).

Upon failure, tpunsubscribe() returns -1 and sets tperrno to indicate the error condition.

Errors

Upon failure, tpunsubscribe() sets tperrno to one of the following values. (Unless otherwise noted, failure does not affect the caller's transaction, if one exists.)

[TPEINVAL]

Invalid arguments were given (for example, subscription is an invalid subscription handle).

[TPENOENT]

Cannot access the BEA Tuxedo EventBroker.

[TPETIME]

This error code indicates that either a timeout has occurred or tpunsubscribe() has been attempted, in spite of the fact that the current transaction is already marked rollback only.

If the caller is in transaction mode, then either the transaction is already rollback only or a transaction timeout has occurred. The transaction is marked abort-only. If the caller is not in transaction mode, a blocking timeout has occurred. (A blocking timeout cannot occur if TPNOBLOCK and/or TPNOTIME is specified.)

If a transaction timeout has occurred, then, with one exception, any attempts to send new requests or receive outstanding replies will fail with TPETIME until the transaction has been aborted. The exception is a request that does not block, expects no reply, and is not sent on behalf of the caller's transaction (that is, tpacall() with TPNOTRAN, TPNOBLOCK, and TPNOREPLY set).

When a transactional ATMI call fails inside a transaction, the transaction is put into the TX_ROLLBACK_ONLY state. This state is treated, for most purposes, as though it were equivalent to a timeout. All further ATMI calls for this transaction (with the exception of those issued in the circumstances described in the previous paragraph) will fail with TPETIME.

[TPEBLOCK]

A blocking condition exists and TPNOBLOCK was specified.

[TPGOTSIG]

A signal was received and TPSIGRSTRT was not specified.

[TPEPROTO]

tpunsubscribe() was called improperly.

[TPESYSTEM]

A BEA Tuxedo system error has occurred. The exact nature of the error is written to a log file.

[TPEOS]

An operating system error has occurred.