Tribblix: manual page: t

T_RCVUDERR(3NSL) Networking Services Library Functions T_RCVUDERR(3NSL)

NAME

t_rcvuderr - receive a unit data error indication

SYNOPSIS

#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, 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 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. The argument 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 netbuf addr;
struct netbuf opt;
t_scalar_t error;

The maxlen field of addr and opt must be set before calling 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.

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_IDLE.

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 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 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:
#include <tiuser.h>

Error Description Values

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

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.

ATTRIBUTES