T_RCVUDERR(3NSL)T_RCVUDERR(3NSL)NAMEt_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 trans‐
port 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 func‐
tion 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 identi‐
fies options that were associated with the data unit, and error speci‐
fies 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 trans‐
port 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 dis‐
carded.
TNOTSUPPORT
This function is not supported by the underlying trans‐
port 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 differ‐
ent 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 circum‐
stances 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
See attributes(5) for descriptions of the following attributes:
┌───────────────┬─────────────────┐
│ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├───────────────┼─────────────────┤
│MT Level │ Safe │
└───────────────┴─────────────────┘
SEE ALSOt_rcvudata(3NSL), t_sndudata(3NSL), attributes(5)
May 7, 1998 T_RCVUDERR(3NSL)
