[apple/libc.git] / net / sockatmark.3

.\" Copyright (c) 2002 William C. Fenner.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD: src/lib/libc/net/sockatmark.3,v 1.4 2002/12/19 09:40:22 ru Exp $
.\"
.Dd October 13, 2002
.Dt SOCKATMARK 3
.Os
.Sh NAME
.Nm sockatmark
.Nd determine whether the read pointer is at the OOB mark
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/socket.h
.Ft int
.Fn sockatmark "int s"
.Sh DESCRIPTION
To find out if the read pointer is currently pointing at
the mark in the data stream, the
.Fn sockatmark
function is provided.
If
.Fn sockatmark
returns 1, the next read will return data
after the mark.
Otherwise (assuming out of band data has arrived),
the next read will provide data sent by the client prior
to transmission of the out of band signal.
The routine used
in the remote login process to flush output on receipt of an
interrupt or quit signal is shown below.
It reads the normal data up to the mark (to discard it),
then reads the out-of-band byte.
.Bd -literal -offset indent
#include <sys/socket.h>
\&...
oob()
{
	int out = FWRITE, mark;
	char waste[BUFSIZ];

	/* flush local terminal output */
	ioctl(1, TIOCFLUSH, (char *)&out);
	for (;;) {
		if ((mark = sockatmark(rem)) < 0) {
			perror("sockatmark");
			break;
		}
		if (mark)
			break;
		(void) read(rem, waste, sizeof (waste));
	}
	if (recv(rem, &mark, 1, MSG_OOB) < 0) {
		perror("recv");
		...
	}
	...
}
.Ed
.Sh RETURN VALUES
Upon successful completion, the
.Fn sockatmark
function returns the value 1 if the read pointer is pointing at
the OOB mark, 0 if it is not.
Otherwise, the value \-1 is returned
and the global variable
.Va errno
is set to
indicate the error.
.Sh ERRORS
The
.Fn sockatmark
call fails if:
.Bl -tag -width Er
.It Bq Er EBADF
The
.Fa s
argument
is not a valid descriptor.
.It Bq Er ENOTTY
The
.Fa s
argument
is a descriptor for a file, not a socket.
.El
.Sh SEE ALSO
.Xr recv 2 ,
.Xr send 2
.Sh HISTORY
The
.Fn sockatmark
function was introduced by
.St -p1003.1-2001 ,
to standardize the historical
.Dv SIOCATMARK
.Xr ioctl 2 .
The
.Er ENOTTY
error instead of the usual
.Er ENOTSOCK
is to match the historical behavior of
.Dv SIOCATMARK .
Commit	Line	Data
224c7076 A	1	.\" Copyright (c) 2002 William C. Fenner. All rights reserved.
	2	.\"
	3	.\" Redistribution and use in source and binary forms, with or without
	4	.\" modification, are permitted provided that the following conditions
	5	.\" are met:
	6	.\" 1. Redistributions of source code must retain the above copyright
	7	.\" notice, this list of conditions and the following disclaimer.
	8	.\" 2. Redistributions in binary form must reproduce the above copyright
	9	.\" notice, this list of conditions and the following disclaimer in the
	10	.\" documentation and/or other materials provided with the distribution.
	11	.\"
	12	.\" THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
	13	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	14	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	15	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	16	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	17	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	18	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	19	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	20	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	21	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	22	.\" SUCH DAMAGE.
	23	.\"
	24	.\" $FreeBSD: src/lib/libc/net/sockatmark.3,v 1.4 2002/12/19 09:40:22 ru Exp $
	25	.\"
	26	.Dd October 13, 2002
	27	.Dt SOCKATMARK 3
	28	.Os
	29	.Sh NAME
	30	.Nm sockatmark
	31	.Nd determine whether the read pointer is at the OOB mark
	32	.Sh LIBRARY
	33	.Lb libc
	34	.Sh SYNOPSIS
	35	.In sys/socket.h
	36	.Ft int
	37	.Fn sockatmark "int s"
	38	.Sh DESCRIPTION
	39	To find out if the read pointer is currently pointing at
	40	the mark in the data stream, the
	41	.Fn sockatmark
	42	function is provided.
	43	If
	44	.Fn sockatmark
	45	returns 1, the next read will return data
	46	after the mark.
	47	Otherwise (assuming out of band data has arrived),
	48	the next read will provide data sent by the client prior
	49	to transmission of the out of band signal.
	50	The routine used
	51	in the remote login process to flush output on receipt of an
	52	interrupt or quit signal is shown below.
	53	It reads the normal data up to the mark (to discard it),
	54	then reads the out-of-band byte.
	55	.Bd -literal -offset indent
	56	#include <sys/socket.h>
	57	\&...
	58	oob()
	59	{
	60	int out = FWRITE, mark;
	61	char waste[BUFSIZ];
	62
	63	/* flush local terminal output */
	64	ioctl(1, TIOCFLUSH, (char *)&out);
65	for (;;) {
66	if ((mark = sockatmark(rem)) < 0) {
67	perror("sockatmark");
68	break;
69	}
70	if (mark)
71	break;
72	(void) read(rem, waste, sizeof (waste));
73	}
74	if (recv(rem, &mark, 1, MSG_OOB) < 0) {
75	perror("recv");
76	...
77	}
78	...
79	}
80	.Ed
81	.Sh RETURN VALUES
82	Upon successful completion, the
83	.Fn sockatmark
84	function returns the value 1 if the read pointer is pointing at
85	the OOB mark, 0 if it is not.
86	Otherwise, the value \-1 is returned
87	and the global variable
88	.Va errno
89	is set to
90	indicate the error.
91	.Sh ERRORS
92	The
93	.Fn sockatmark
94	call fails if:
95	.Bl -tag -width Er
96	.It Bq Er EBADF
97	The
98	.Fa s
99	argument
100	is not a valid descriptor.
101	.It Bq Er ENOTTY
102	The
103	.Fa s
104	argument
105	is a descriptor for a file, not a socket.
106	.El
107	.Sh SEE ALSO
108	.Xr recv 2 ,
109	.Xr send 2
110	.Sh HISTORY
111	The
112	.Fn sockatmark
113	function was introduced by
114	.St -p1003.1-2001 ,
115	to standardize the historical
116	.Dv SIOCATMARK
117	.Xr ioctl 2 .
118	The
119	.Er ENOTTY
120	error instead of the usual
121	.Er ENOTSOCK
122	is to match the historical behavior of
123	.Dv SIOCATMARK .