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.\" Copyright 1989 AT&T
.\" Copyright (c) 2005, Sun Microsystems, Inc.  All Rights Reserved
.\" Copyright 2020 Robert Mustacchi
.\"
.Dd "March 25, 2020"
.Dt FERROR 3C
.Os
.Sh NAME
.Nm ferror ,
.Nm feof ,
.Nm clearerr ,
.Nm fileno
.Nd stream status inquiries
.Sh SYNOPSIS
.In stdio.h
.Ft int
.Fo ferror
.Fa "FILE *stream"
.Fc
.Ft int
.Fo feof
.Fa "FILE *stream"
.Fc
.Ft void
.Fo clearerr
.Fa "FILE *stream"
.Fc
.Ft int
.Fo fileno
.Fa "FILE *stream"
.Fc
.Sh DESCRIPTION
The
.Fn ferror
function returns a non-zero value when an error has
previously occurred reading from or writing to the named
.Fa stream
.Po
see
.Xr Intro 3
.Pc .
It returns
.Sy 0
otherwise.
.Pp
The
.Fn feof
function returns a non-zero value when
.Sy EOF
has previously been detected reading the named input
.Fa stream .
It returns
.Sy 0
otherwise.
.Pp
The
.Fn clearerr
function resets the error indicator and
.Sy EOF
indicator to 0 on the named
.Fa stream .
.Pp
The
.Fn fileno
function returns the integer file descriptor associated with
the named
.Fa stream ;
see
.Xr open 2 .
Streams that are not associated with a file descriptor such as those
that were created through the
.Xr fmemopen 3C
or
.Xr open_memstream 3C
functions will return
.Sy -1 .
.Sh INTERFACE STABILITY
.Sy Standard
.Sh MT-LEVEL
.Sy MT-Safe
.Sh SEE ALSO
.Xr Intro 2 ,
.Xr open 2 ,
.Xr fmemopen 3C ,
.Xr fopen 3C ,
.Xr open_memstream 3C ,
.Xr stdio 3C