t_sync Subroutine for X/Open Transport Interface

AIX Version 4.3 Communications Technical Reference, Volume 2

t_sync Subroutine for X/Open Transport Interface

Purpose

Synchronize transport library.

Library

X/Open Transport Interface Library (libxti.a)

Syntax

#include <xti.h>

int t_sync (fd)
int fd;

Description

The t_sync subroutine synchronizes the data structures managed by the transport library with information from the underlying transport provider. In doing so, if the file descriptor referenced a transport endpoint, the subroutine can convert an uninitialized file descriptor (obtained using the open or dup subroutines or as a result of a fork operation and an exec operation) to an initialized transport endpoint, by updating and allocating the necessary library data structures. This subroutine also allows two cooperating processes to synchronize their interaction with a transport provider.

For example, if a process forks a new process and issues an exec operation, the new process must issue a t_sync to build the private library data structure associated with a transport endpoint and to synchronize the data structure with the relevant provider information.

It is important to remember that the transport provider treats all users of a transport endpoint as a single user. If multiple processes are using the same endpoint, they should coordinate their activities so as not to violate the state of the transport endpoint. The t_sync subroutine returns the current state of the transport endpoint to the user, thereby enabling the user to verify the state before taking further action. This coordination is only valid among cooperating processes; it is possible that a process or an incoming event could change the endpoint's state after a t_sync call is issued.

If the transport endpoint is undergoing a state transition when the t_sync subroutine is called, the subroutine will fail.

Parameter

fd	Specifies the transport endpoint.

Valid States

ALL - except T_UNINIT.

Return Values

On successful completion, the state of the transport endpoint is returned. Otherwise, a value of -1 is returned and t_errno is set to indicate an error. The state returned is one of the following:

T_UNBND	Unbound.
T_IDLE	Idle.
T_OUTCON	Outgoing connection pending.
T_INCON	Incoming connection pending.
T_DATAXFER	Data transfer.
T_OUTREL	Outgoing orderly release (waiting for an orderly release indication).
T_INREL	Incoming orderly release (waiting for an orderly release request).

Error Codes

On failure, t_errno is set to one of the following:

TBADF	The specified file descriptor does not refer to a transport endpoint. This error may be returned when the fd parameter has been previously closed or an erroneous number may have been passed to the call.
TPROTO	This error indicates that a communication problem has been detected between the X/Open Transport Interface and the transport provider for which there is no other suitable X/Open Transport Interface (t_errno).
TSTATECHNG	The transport endpoint is undergoing a state change.
TSYSERR	A system error has occurred during execution of this function.

Related Information

The dup subroutine, exec subroutine, fork subroutine, open subroutine.