git.saurik.com Git - apple/libc.git/blame_incremental

... / ...

Commit	Line	Data
	1	.\" Copyright (c) 1990, 1991, 1993
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" This code is derived from software contributed to Berkeley by
	5	.\" Chris Torek and the American National Standards Committee X3,
	6	.\" on Information Processing Systems.
	7	.\"
	8	.\" Redistribution and use in source and binary forms, with or without
	9	.\" modification, are permitted provided that the following conditions
	10	.\" are met:
	11	.\" 1. Redistributions of source code must retain the above copyright
	12	.\" notice, this list of conditions and the following disclaimer.
	13	.\" 2. Redistributions in binary form must reproduce the above copyright
	14	.\" notice, this list of conditions and the following disclaimer in the
	15	.\" documentation and/or other materials provided with the distribution.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)ferror.3 8.2 (Berkeley) 4/19/94
	33	.\" $FreeBSD: src/lib/libc/stdio/ferror.3,v 1.13 2009/01/28 14:38:41 trhodes Exp $
	34	.\"
	35	.Dd January 28, 2009
	36	.Dt FERROR 3
	37	.Os
	38	.Sh NAME
	39	.Nm clearerr ,
	40	.Nm clearerr_unlocked ,
	41	.Nm feof ,
	42	.Nm feof_unlocked ,
	43	.Nm ferror ,
	44	.Nm ferror_unlocked ,
	45	.Nm fileno ,
	46	.Nm fileno_unlocked
	47	.Nd check and reset stream status
	48	.Sh LIBRARY
	49	.Lb libc
	50	.Sh SYNOPSIS
	51	.In stdio.h
	52	.Ft void
	53	.Fn clearerr "FILE *stream"
	54	.Ft void
	55	.Fn clearerr_unlocked "FILE *stream"
	56	.Ft int
	57	.Fn feof "FILE *stream"
	58	.Ft int
	59	.Fn feof_unlocked "FILE *stream"
	60	.Ft int
	61	.Fn ferror "FILE *stream"
	62	.Ft int
	63	.Fn ferror_unlocked "FILE *stream"
	64	.Ft int
	65	.Fn fileno "FILE *stream"
	66	.Ft int
	67	.Fn fileno_unlocked "FILE *stream"
	68	.Sh DESCRIPTION
	69	The function
	70	.Fn clearerr
	71	clears the end-of-file and error indicators for the stream pointed
	72	to by
	73	.Fa stream .
	74	.Pp
	75	The function
	76	.Fn feof
	77	tests the end-of-file indicator for the stream pointed to by
	78	.Fa stream ,
	79	returning non-zero if it is set.
	80	The end-of-file indicator may be cleared by explicitly calling
	81	.Fn clearerr ,
	82	or as a side-effect of other operations, e.g.\&
	83	.Fn fseek .
	84	.Pp
	85	The function
	86	.Fn ferror
	87	tests the error indicator for the stream pointed to by
	88	.Fa stream ,
	89	returning non-zero if it is set.
	90	.Pp
	91	The function
	92	.Fn fileno
	93	examines the argument
	94	.Fa stream
	95	and returns its integer descriptor.
	96	.Pp
	97	The
	98	.Fn clearerr_unlocked ,
	99	.Fn feof_unlocked ,
	100	.Fn ferror_unlocked ,
	101	and
	102	.Fn fileno_unlocked
	103	functions are equivalent to
	104	.Fn clearerr ,
	105	.Fn feof ,
	106	.Fn ferror ,
	107	and
	108	.Fn fileno
	109	respectively, except that the caller is responsible for locking the stream
	110	with
	111	.Xr flockfile 3
	112	before calling them.
	113	These functions may be used to avoid the overhead of locking the stream
	114	and to prevent races when multiple threads are operating on the same stream.
	115	.Sh ERRORS
	116	These functions should not fail and do not set the external
	117	variable
	118	.Va errno .
	119	.Sh SEE ALSO
	120	.Xr open 2 ,
	121	.Xr fdopen 3 ,
	122	.Xr flockfile 3 ,
	123	.Xr stdio 3
	124	.Sh STANDARDS
	125	The functions
	126	.Fn clearerr ,
	127	.Fn feof ,
	128	and
	129	.Fn ferror
	130	conform to
	131	.St -isoC .