isastream.3

7号信令功能代码,为开源代码

'\" rtp
.\" -*- nroff -*-
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.\" @(#) isastream.3,v 1.1.1.1.8.1 2004/01/12 23:32:49 brian Exp
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.\" Modified 2004/01/12 23:32:49 by brian
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.\" Copyright (C) 2000  John A. Boyd Jr.  protologos, LLC
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.\"
.\"
.TH ISASTREAM 3 "2004/01/12 23:32:49" "LiS-2_16_18-8" "Linux STREAMS"
.SH NAME
.B isastream
\- determine whether an open file is \fISTREAMS\fR
.SH SYNOPSIS
.PP
.B "#include <stropts.h> "
.HP
.BI "int isastream( int " filedes " ); "
.SH DESCRIPTION
.PP
.BR isastream "() "
may be used to test whether or not an open file descriptor is for a
.I STREAMS
file (see
.IR STREAMS "(4)).  "
.SH "RETURN VALUE"
.PP
Upon successful completion,
.BR isastream "() "
returns 1 if the indicated file is a
.IR STREAM ,
and 0 if it is not.
If
.I filedes
does not identify a valid open file,
.BR isastream "() "
should return -1 with
.I errno
set to
.BR EBADF .
.SH "APPLICATION USAGE"
.PP
.BR isastream "() " 
is convenient under Linux for determining or at least estimating
a file's behavior, since (with Linux
.I STREAMS
being available) there are both
.I STREAMS
and
.RI "non-" STREAMS
implementations for, e.g.,
.I fifos
(also known as
.I "named pipes"
- see
.BR fifo "(4)) "
and
.I pipes
(see
.BR pipe "(3)).  "
.sp
.BR isastream "() "
is also useful in conjunction with
.BR fattach "(3) "
and
.BR fdetach "(3) "
to determine whether or not a
.I STREAMS
file has been attached to a path name.
.sp
Applications wishing to use the version of the
.BR isastream "() "
function described herein must link with the
.B LiS
.[
LiS
.]
library which provides it.  The Linux/GNU C library otherwise provides a stub
supporting calls to
.BR isastream "() "
which only generates an error indicating that it is not implemented.
.SH "CONFORMING TO"
.PP
UNIX\(rg\ System V Release 4 (SVR4)
.[
svr4
.]
.SH "SEE ALSO"
.PP
.BR pipe "(3), "
.BR fattach "(3), "
.BR fdetach "(3), "
.BR fattach "(8), "
.BR fdetach "(8), "
.BR fifo "(4), "
.BR STREAMS "(4) "
.SH AUTHOR
.PP
John Boyd, protologos LLC.
.[
$LIST$
.]
.TI