1.\" $OpenBSD: ferror.3,v 1.6 2003/06/02 20:18:36 millert Exp $ 2.\" 3.\" Copyright (c) 1990, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" Chris Torek and the American National Standards Committee X3, 8.\" on Information Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.Dd April 19, 1994 35.Dt FERROR 3 36.Os 37.Sh NAME 38.Nm clearerr , 39.Nm feof , 40.Nm ferror , 41.Nm fileno 42.Nd check and reset stream status 43.Sh SYNOPSIS 44.Fd #include <stdio.h> 45.Ft void 46.Fn clearerr "FILE *stream" 47.Ft int 48.Fn feof "FILE *stream" 49.Ft int 50.Fn ferror "FILE *stream" 51.Ft int 52.Fn fileno "FILE *stream" 53.Sh DESCRIPTION 54The function 55.Fn clearerr 56clears the end-of-file and error indicators for the stream pointed to by 57.Fa stream . 58.Pp 59The function 60.Fn feof 61tests the end-of-file indicator for the stream pointed to by 62.Fa stream , 63returning non-zero if it is set. 64The end-of-file indicator can only be cleared by the function 65.Fn clearerr . 66.Pp 67The function 68.Fn ferror 69tests the error indicator for the stream pointed to by 70.Fa stream , 71returning non-zero if it is set. 72The error indicator can only be reset by the 73.Fn clearerr 74function. 75.Pp 76The function 77.Fn fileno 78examines the argument 79.Fa stream 80and returns its integer file descriptor. 81.Sh ERRORS 82These functions should not fail and do not set the external 83variable 84.Va errno . 85.Sh SEE ALSO 86.Xr open 2 , 87.Xr stdio 3 88.Sh STANDARDS 89The functions 90.Fn clearerr , 91.Fn feof , 92and 93.Fn ferror 94conform to 95.St -ansiC . 96The function 97.Fn fileno 98conforms to 99.St -p1003.1-90 . 100