'\" te
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.TH ISASTREAM 3C "May 23, 2021"
.SH NAME
isastream \- test a file descriptor
.SH SYNOPSIS
.nf
#include <stropts.h>

\fBint\fR \fBisastream\fR(\fBint\fR \fIfildes\fR);
.fi

.SH DESCRIPTION
The \fBisastream()\fR function determines if a file descriptor represents a
STREAMS file. The \fIfildes\fR argument refers to an open file descriptor.
.SH RETURN VALUES
Upon successful completion, \fBisastream()\fR returns \fB1\fR if \fIfildes\fR
represents a STREAMS file, and \fB0\fR if it does not.  Otherwise, \fB\(mi1\fR
is return and \fBerrno\fR is set to indicate the error.
.SH ERRORS
The \fBisastream()\fR function will fail if:
.sp
.ne 2
.na
\fB\fBEBADF\fR\fR
.ad
.RS 9n
The \fIfildes\fR argument is not a valid file descriptor.
.RE

.SH ATTRIBUTES
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
_
MT-Level	MT-Safe
.TE

.SH SEE ALSO
.BR streamio (4I),
.BR attributes (7),
.BR standards (7)
.sp
.LP
\fISTREAMS Programming Guide\fR