t_rcvdis.3xti

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3XTI 代码 · 共 116 行

.TH t_rcvdis 3xti
.SH Name
t_rcvdis \- retrieve information from disconnect
.SH Syntax
.B #include <xti.h>
.br
.sp 1
.B int t_rcvdis(\fIfd, discon\fB)
.br
.B int \fIfd\fB;
.br
.B struct t_discon \fI*discon\fB;
.SH Arguments
.IP \fIfd\fR 10
Identifies the local transport endpoint. 
.IP \fIdiscon\fR 10
Points to a \fBt_discon\fR structure containing the following members:
.EX
struct netbuf \fIudata\fP;
int \fIreason\fP;
int \fIsequence\fR:
.EE
.IP
The members of the \fIt_discon\fR struct have the following meanings:
.RS 10
.IP \fIudata\fR 12
Identifies any user data that was sent with the disconnect.
.IP \fIreason\fR
Specifies the reason for the disconnect through a protocol-dependent reason code.
.IP \fIsequence\fR
Identifies an outstanding connect indication with which the connection is 
associated. The \fIsequence\fR field is only meaningful when 
.PN t_rcvdis()
is issued by a passive transport user who has executed 
one or more 
.Pn t_listen()
functions and is processing the resulting 
connect indications. If a disconnect indication occurs, \fIsequence\fP can 
be used to identify which of the outstanding connect indications is associated
with the disconnect.
.RE
.SH Description
This function is used to identify the cause of a disconnect and to
retrieve any user data sent with the disconnect.
.NXR "t_rcvdis system call"
.NXR "disconnect" "retrieving information"
.PP
If a user does not care if there is incoming data and does not need to
know the value of \fIreason\fR or \fIsequence\fR, \fIdiscon\fR may be
NULL and any user data associated with the disconnect is discarded.
However, if a user has retrieved more than one outstanding connect
indication, by means of 
.PN t_listen()
and \fIdiscon\fR is NULL, the user will be unable to identify with which connect indication the
disconnect is associated.
.PP
.TS
tab(@);
lfHB lfHB lfHB
lfR  lfR  lfR .
_
.sp 6p
Parameters@Before Call@After Call
.sp 6p
_
.sp 6p
fd@x@/
discon->udata.maxlen@x@/
discon->udata.len@/@x
discon->udata.buf@x@(?)
discon->reason@/@x
discon->sequence@/@?
.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 
.PN t_errno()
is set to indicate the error.
.SH Diagnostics
On failure, \fBt_errno\fR is set to one of the following:
.TP 20
[TBADF]
The specified file descriptor \fIfd\fR  does not refer to a
transport endpoint.
.TP 20 
[TOUTSTATE]
The function was issued in the wrong sequence on the transport endpoint
referenced by \fIfd\fR.
.TP 20
[TNODIS]
No disconnect indication currently exists on the specified transport
endpoint.
.TP 20
[TBUFOVFLW]
The number of bytes allocated for incoming data is not sufficient to
store the data. If \fIfd\fR is a passive endpoint with \fIocnt\fR > 1,
it remains in state T_INCON; otherwise, the endpoint state is
set to T_IDLE. The disconnect indication information to be
returned in \fIdiscon\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_alloc(3xti),
t_connect(3xti), 
t_listen(3xti), 
t_open(3xti),
t_snddis(3xti)