PURPOSE

tpconnect - routine for establishing a conversational service connection

SYNOPSIS

#include <atmi.h>
int tpconnect(char *svc, char *data, long len, long flags)

DESCRIPTION

tpconnect() allows a program to set up a half-duplex connection to a conversational service, svc. The name must be one of the conversational service names posted by a conversational server.

As part of setting up a connection, the caller can pass application defined data to the listening program. If the caller chooses to pass data, then data must point to a buffer previously allocated by tpalloc(3c). len specifies how much of the buffer to send. Note that if data points to a buffer of a 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 can be NULL in which case len is ignored (no application data is passed to the conversational service). The type and sub-type of data must match one of the types and sub-types recognized by svc. data and len are passed to the conversational service via the TPSVCINFO structure with which the service is invoked; the service does not have to call tprecv(3c) to get the data.

Following is a list of valid flags.

TPNOTRAN

If the caller is in transaction mode and this flag is set, then when svc is invoked, it is not performed on behalf of the caller's transaction. Note that svc may still be invoked in transaction mode but it will not be the same transaction: a svc may have as a configuration attribute that it is automatically invoked in transaction mode. A caller in transaction mode that sets this flag is still subject to the transaction timeout (and no other). If a service fails that was invoked with this flag, the caller's transaction is not affected.

TPSENDONLY

The caller wants the connection to be set up initially such that it can only send data and the called service can only receive data (that is, the caller initially has control of the connection). Either TPSENDONLY or TPRECVONLY must be specified.

TPRECVONLY

The caller wants the connection to be set up initially such that it can only receive data and the called service can only send data (that is, the service being called initially has control of the connection). Either TPSENDONLY or TPRECVONLY must be specified.

TPNOBLOCK

The connection is not established and the data is not sent if a blocking condition exists (for example, the data buffers through which the message is sent are full). Note that this flag applies only to the send portion of tpconnect(); the function may block waiting for an acknowledgement from the server. When TPNOBLOCK is not specified and a blocking condition exists, the caller blocks until the condition subsides or a blocking timeout or transaction timeout occurs.

TPNOTIME

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

TPSIGRSTRT

If a signal interrupts any underlying system calls, then the interrupted call is re-issued.

RETURN VALUES

Upon successful completion, tpconnect() returns a descriptor that is used to refer to the connection in subsequent calls. Otherwise it returns -1 and sets tperrno to indicate the error condition.

ERRORS

Under the following conditions, tpconnect() fails and sets tperrno to an error code listed below. (Unless otherwise noted, failure does not affect the caller's transaction, if one exists)

[TPEINVAL]

Invalid arguments were given (for example, svc is NULL, data is non-NULL and does not point to a buffer allocated by tpalloc(3c), TPSENDONLY or TPRECVONLY was not specified in flags, or flags are otherwise invalid).

[TPENOENT]

Cannot initiate a connection to svc because it does not exist or is not a conversational service or the name begins with "..".

[TPEITYPE]

The type and subtype of data is not one of the allowed types and subtypes that svc accepts.

[TPELIMIT]

The caller's request was not sent because the maximum number of outstanding connections has been reached.

[TPETRAN]

svc belongs to a program that does not support transactions and TPNOTRAN was not set.

[TPETIME]

A timeout occurred. If the caller is in transaction mode, then a transaction timeout occurred and the transaction is marked abort-only; otherwise, a blocking timeout occurred and neither TPNOBLOCK nor TPNOTIME were specified. If a transaction timeout occurred, then any attempts to send or receive messages on any connections or to start a new connection will fail with TPETIME until the transaction has been aborted.

[TPEBLOCK]

A blocking condition exists and TPNOBLOCK was specified.

[TPGOTSIG]

A signal was received and TPSIGRSTRT was not specified.

[TPEPROTO]

tpconnect() 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.

SEE ALSO

tpalloc(3c),
tpdiscon(3c),
tprecv(3c),
tpsend(3c),
tpservice(3c)