[apple/xnu.git] / bsd / man / man2 / fsync.2

.\"	$NetBSD: fsync.2,v 1.4 1995/02/27 12:32:38 cgd Exp $
.\"
.\" Copyright (c) 1983, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)fsync.2	8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.Dt FSYNC 2
.Os BSD 4.2
.Sh NAME
.Nm fsync
.Nd "synchronize a file's in-core state with that on disk"
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Ft int
.Fn fsync "int fd"
.Sh DESCRIPTION
.Fn Fsync
causes all modified data and attributes of
.Fa fd
to be moved to a permanent storage device.
This normally results in all in-core modified copies
of buffers for the associated file to be written to a disk.
.Pp
.Fn Fsync
should be used by programs that require a file to be
in a known state, for example, in building a simple transaction
facility.
.Sh RETURN VALUES
A 0 value is returned on success.  A -1 value indicates
an error.
.Sh ERRORS
The
.Fn fsync
fails if:
.Bl -tag -width Er
.It Bq Er EBADF
.Fa fd
is not a valid descriptor.
.It Bq Er EINVAL
.Fa fd
refers to a socket, not to a file.
.It Bq Er EIO
An I/O error occurred while reading from or writing to the file system.
.El
.Sh SEE ALSO
.Xr sync 2 ,
.Xr sync 8 ,
.Xr update 8
.Sh HISTORY
The
.Fn fsync
function call appeared in
.Bx 4.2 .
Commit	Line	Data
9bccf70c A	1	.\" $NetBSD: fsync.2,v 1.4 1995/02/27 12:32:38 cgd Exp $
	2	.\"
	3	.\" Copyright (c) 1983, 1993
	4	.\" The Regents of the University of California. All rights reserved.
	5	.\"
	6	.\" Redistribution and use in source and binary forms, with or without
	7	.\" modification, are permitted provided that the following conditions
	8	.\" are met:
	9	.\" 1. Redistributions of source code must retain the above copyright
	10	.\" notice, this list of conditions and the following disclaimer.
	11	.\" 2. Redistributions in binary form must reproduce the above copyright
	12	.\" notice, this list of conditions and the following disclaimer in the
	13	.\" documentation and/or other materials provided with the distribution.
	14	.\" 3. All advertising materials mentioning features or use of this software
	15	.\" must display the following acknowledgement:
	16	.\" This product includes software developed by the University of
	17	.\" California, Berkeley and its contributors.
	18	.\" 4. 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	.\" @(#)fsync.2 8.1 (Berkeley) 6/4/93
	35	.\"
	36	.Dd June 4, 1993
	37	.Dt FSYNC 2
	38	.Os BSD 4.2
	39	.Sh NAME
	40	.Nm fsync
	41	.Nd "synchronize a file's in-core state with that on disk"
	42	.Sh SYNOPSIS
	43	.Fd #include <unistd.h>
	44	.Ft int
	45	.Fn fsync "int fd"
	46	.Sh DESCRIPTION
	47	.Fn Fsync
	48	causes all modified data and attributes of
	49	.Fa fd
	50	to be moved to a permanent storage device.
	51	This normally results in all in-core modified copies
	52	of buffers for the associated file to be written to a disk.
	53	.Pp
	54	.Fn Fsync
	55	should be used by programs that require a file to be
	56	in a known state, for example, in building a simple transaction
	57	facility.
	58	.Sh RETURN VALUES
	59	A 0 value is returned on success. A -1 value indicates
	60	an error.
	61	.Sh ERRORS
	62	The
	63	.Fn fsync
	64	fails if:
65	.Bl -tag -width Er
66	.It Bq Er EBADF
55e303ae	67	.Fa fd
9bccf70c A	68	is not a valid descriptor.
9bccf70c A	69	.It Bq Er EINVAL
55e303ae	70	.Fa fd
9bccf70c A	71	refers to a socket, not to a file.
	72	.It Bq Er EIO
	73	An I/O error occurred while reading from or writing to the file system.
	74	.El
	75	.Sh SEE ALSO
	76	.Xr sync 2 ,
	77	.Xr sync 8 ,
	78	.Xr update 8
	79	.Sh HISTORY
	80	The
	81	.Fn fsync
	82	function call appeared in
	83	.Bx 4.2 .