t_rcvdis

- retrieve information from disconnection

Synopsis

#include <xti.h>

int t_rcvdis(int fd, struct t_discon *discon);

Description

This routine is part of the XTI interfaces which evolved from the TLI interfaces. XTI represents the future evolution of these interfaces. However, TLI interfaces are supported for compatibility. When using a TLI routine that has the same name as an XTI routine, the tiuser.h header file must be used. Refer to the TLI COMPATIBILITY section for a description of differences between the two interfaces.

This function is used to identify the cause of a disconnection and to retrieve any user data sent with the disconnection. The argument fd identifies the local transport endpoint where the connection existed, and discon points to a t_discon structure containing the following members:

struct netbuf udata;
int reason;
int sequence;

The field reason specifies the reason for the disconnection through a protocol-dependent reason code, udata identifies any user data that was sent with the disconnection, and sequence may identify an outstanding connection indication with which the disconnection is associated. The field sequence is only meaningful when t_rcvdis() is issued by a passive transport user who has executed one or more t_listen(3NSL) functions and is processing the resulting connection indications. If a disconnection indication occurs, sequence can be used to identify which of the outstanding connection indications is associated with the disconnection.

The maxlen field of udata may be set to zero, if the user does not care about incoming data. If, in addition, the user does not need to know the value of reason or sequence, discon may be set to NULL and any user data associated with the disconnection indication shall be discarded. However, if a user has retrieved more than one outstanding connection indication by means of t_listen(3NSL), and discon is a null pointer, the user will be unable to identify with which connection indication the disconnection is associated.

Return Values

Upon successful completion, a value of 0 is returned. Otherwise, a value of –1 is returned and t_errno is set to indicate an error.

VALID STATES

T_DATAXFER, T_OUTCON, T_OUTREL, T_INREL, T_INCON(ocnt > 0).

Errors

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

TBADF

The specified file descriptor does not refer to a transport endpoint.

TBUFOVFLW

The number of bytes allocated for incoming data (maxlen) is greater than 0 but not sufficient to store the data. If fd is a passive endpoint with ocnt > 1, it remains in state T_INCON; otherwise, the endpoint state is set to T_IDLE.

TNODIS

No disconnection indication currently exists on the specified transport endpoint.

TNOTSUPPORT

This function is not supported by the underlying transport provider.

TOUTSTATE

The communications endpoint referenced by fd is not in one of the states in which a call to this function is valid.

TPROTO

This error indicates that a communication problem has been detected between XTI and the transport provider for which there is no other suitable XTI error (t_errno).

TSYSERR

A system error has occurred during execution of this function.

TLI COMPATIBILITY

The XTI and TLI interface definitions have common names but use different header files. This, and other semantic differences between the two interfaces are described in the subsections below.

Interface Header

The XTI interfaces use the header file, xti.h. TLI interfaces should not use this header. They should use the header:

Error Description Values

The t_errno values TPROTO and TOUTSTATE can be set by the XTI interface but not by the TLI interface.

A failure return, and a t_errno value that this routine can set under different circumstances than its XTI counterpart is TBUFOVFLW. It can be returned even when the maxlen field of the corresponding buffer has been set to zero.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

t_alloc(3NSL), t_connect(3NSL), t_listen(3NSL), t_open(3NSL), t_snddis(3NSL), attributes(5)