t_rcvuderr(3N)

NAME

t_rcvuderr − receive a unit data error indication

SYNOPSIS

cc [ flag ... ] file ... −lnsl [ library ... ]

#include <xti.h>

int t_rcvuderr(int fd, struct t_uderr ∗uderr);

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, a different header file, tiuser.h , must be used. Refer to the section, TLI COMPATIBILITY , for a description of differences between the two interfaces.

This function is used in connectionless mode to receive information concerning an error on a previously sent data unit, and should only be issued following a unit data error indication. It informs the transport user that a data unit with a specific destination address and protocol options produced an error. fd identifies the local transport endpoint through which the error report will be received, and uderr points to a t_uderr structure containing the following members:

struct netbufaddr;
struct netbufopt;
longerror;

(maxlen and other members of netbuf are described in t_connect(3N).) The maxlen field of addr and opt must be set before issuing this function to indicate the maximum size of the buffer for each. If this field is set to zero for addr or opt, no information is returned in the buf field of this parameter.

On return from this call, the addr structure specifies the destination protocol address of the erroneous data unit, the opt structure identifies options that were associated with the data unit, and error specifies a protocol-dependent error code.

If the user does not care to identify the data unit that produced an error, uderr may be set to a null pointer and t_rcvuderr() will simply clear the error indication without reporting any information to the user.

VALID STATES

The only legitimate state (see t_getstate(3N)) for a call to this routine is T_IDLE .

RETURN VALUES

t_rcvuderr() returns:

0 On success.

−1 On failure.

On failure, t_errno is set to indicate the error, and possibly errno is set.

ERRORS

On failure, t_errno will be 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 the incoming protocol address or options (maxlen) is greater than 0 but not sufficient to store the information. The unit data error information to be returned in uderr will be discarded.

TNOTSUPPORT This function is not supported by the underlying transport provider.

TNOUDERR No unit data error indication currently exists on the specified transport endpoint.

TOUTSTATE The communications endpoint referenced by fd or resfd 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 t_errno value.

TSYSERR A system error has occurred during execution of this function, errno will be set to the specific error.

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:

#include <tiuser.h>

Error Description Values

The t_errno values that can be set by the XTI interface and cannot be set by the TLI interface are:

TPROTO

TOUTSTATE

A t_errno value that this routine can return 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.

Option Buffers

The format of the options in an opt buffer is dictated by the transport provider. Unlike the XTI interface, the TLI interface does not fix the buffer format.

For more information refer to the Transport Interfaces Programming Guide.

ATTRIBUTES

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

ATTRIBUTE TYPE	ATTRIBUTE VALUE
MT-Level	MT-Safe

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