PURPOSE

tpbroadcast - routine to broadcast notification by name

SYNOPSIS


#include <atmi.h>
int tpbroadcast(char *lmid, char *usrname, char *cltname, char *data,
  long len, long flags)

DESCRIPTION

tpbroadcast() allows a client or server to send unsolicited messages to registered clients within the system. The target client set consists of those clients matching identifiers passed to tpbroadcast(). Wildcards can be used in specifying identifiers.

lmid, usrname, and cltname are logical identifiers used to select the target client set. A NULL value for any argument constitutes a wildcard for that argument. A wildcard argument matches all client identifiers for that field. A 0-length string for any argument matches only 0-length client identifiers. Each identifier must meet the size restrictions defined for the system to be considered valid, that is, each identifier must be between 0 and MAXTIDENT characters in length.

The data portion of the request is pointed to by data, a buffer previously allocated by tpalloc(3c). len specifies how much of data to send. Note that if data points to a buffer type that does not require a length to be specified (for example, an FML fielded buffer), then len is ignored (and may be 0). Also, data may be NULL, in which case len is ignored. The buffer passes through the typed buffer switch routines just as any other outgoing or incoming message would; for example, encode/decode are performed automatically.

Following is a list of valid flags.

TPNOBLOCK: The request is not sent if a blocking condition exists (for example, the internal buffers into which the message is transferred are full).
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. Upon successful return from tpbroadcast(), the message has been delivered to the system for forwarding to the selected clients. tpbroadcast() does not wait for the message to be delivered to each selected client.

RETURN VALUES

tpbroadcast() returns -1 on failure and sets tperrno to indicate the error condition.

ERRORS

Under the following conditions, tpbroadcast() fails, sends no broadcast messages to application clients, and sets tperrno to:

[TPEINVAL]: Invalid arguments were given (for example, identifiers too long or invalid flags). Note that use of an illegal LMID will cause tpbroadcast() to fail and return TPEINVAL. However, non-existent user or client names will simply successfully broadcast to no one.
[TPETIME]: A blocking timeout occurred and neither TPNOBLOCK nor TPNOTIME was specified.
[TPEBLOCK]: A blocking condition was found on the call and TPNOBLOCK was specified.
[TPGOTSIG]: A signal was received and TPSIGRSTRT was not specified.
[TPEPROTO]: tpbroadcast() was called in an improper context.
[TPESYSTEM]: A System/T error has occurred. The exact nature of the error is written to a log file.
[TPEOS]: An operating system error has occurred.

PORTABILITY

The interfaces described in tpnotify(3c) are supported on native site UNIX-based processors. In addition, the routines tpbroadcast() and tpchkunsol() as well as the function tpsetunsol() are supported on UNIX and MS-DOS workstation processors.

USAGE

Clients that select signal-based notification may not be signal-able by the system due to signal restrictions. When this occurs, the system generates a log message that it is switching notification for the selected client to dip-in and the client is notified then and thereafter via dip-in notification. (See the description of the *RESOURCES NOTIFY parameter in ubbconfig(5) for a detailed discussion of notification methods.)

Note that signaling of clients is always done by the system so that the behavior of notification is consistent regardless of where the originating notification call is made. Because of this, only clients running as the application administrator can use signal-based notification. The id for the application administrator is identified as part of the configuration file for the application.

If signal-based notification is selected for a client, then certain ATMI calls can fail, returning TPGOTSIG due to receipt of an unsolicited message if TPSIGRSTRT is not specified. See ubbconfig(5) and tpinit(3c) for more information on notification method selection.