t_rcvuderr.3xti

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3XTI 代码 · 共 104 行

.TH t_rcvuderr 3xti
.SH Name
t_rcvuderr \- receive a unit error indication 
.SH Syntax 
.B #include <xti.h>
.br
.sp 1
.B int t_rcvuderr(\fIfd, uderr\fB)
.br
.B int \fIfd\fB;
.br
.B struct t_uderr \fI*uderr\fB;
.SH Arguments
.IP \fIfd\fR 10
Identifies the local transport endpoint through which the error report
is received.
.IP \fIuderr\fR 10
Points to a \fBt_uderr\fR structure containing the following members:
.EX
struct netbuf \fIaddr\fP;
struct netbuf \fIopt\fP;
long \fIerror\fR;
.EE
.IP
On return from this call, the members have the following meanings:
.RS 10
.IP \fIaddr\fP 12
Specifies the destination protocol address of the erroneous data unit.
.IP \fIopt\fP
Identifies protocol-specific options that were associated with the data unit.
.IP \fIerror\fR	
Specifies a protocol-dependent error code.
.RE
.SH Description
This function is used in connectionless mode to receive information
concerning an error on a previously sent data unit and should 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.
.NXR "t_tcvuderr system call" 
.NXR "connectionless mode" "receiving error information"
.PP
The \fImaxlen\fR field of \fIaddr\fR and \fIopt\fR must be set before
issuing this function to indicate the maximum size of the buffer for
each.
.PP
If the user does not care to identify the data unit that produced an
error, \fIuderr\fR may be set to NULL, and 
.PN t_rcvuderr() 
simply clears the error indication without reporting any information to the
user.
.sp 10
.PP
.TS
tab(@);
lfHB lfHB lfHB
lfR  lfR  lfR .
_
.sp 6p
Parameters@Before Call@After Call
.sp 6p
_
.sp 6p
fd@x@/
uderr->addr.maxlen@x@/
uderr->addr.len@/@x
uderr->addr.buf@x@(x)
uderr->opt.maxlen@x@/
uderr->opt.len@/@x
uderr->opt.buf@x@(x)
uderr->error@/@x
.sp 6p
_
.TE
.PP
.sp 12p
.SH Return Values
Upon successful completion, a value of 0 is returned. On failure,  a
value of \-1 is returned, and \fBt_errno\fR is set to indicate the
error.
.SH Diagnostics
On failure, \fBt_errno\fR is set to one of the following:
.TP 20
[BADF]
The specified file descriptor does not refer to a transport endpoint.
.TP 20 
[TNOUDERR]
No unit data error indication currently exists on the specified
transport endpoint.
.TP 20
[TBUFOVFLW]
The number of bytes allocated for the incoming protocol address or
options is not sufficient to store the information. The unit data error
information to be returned in \fIuderr\fR will be discarded.
.TP 20
[TNOTSUPPORT]
This function is not supported by the underlying transport provider. 
.TP 20
[TSYSERR]
A system error has occurred during execution of this function.
.SH See Also
t_rcvudata(3xti), 
t_sndudata(3xti)