[unix-history] / lib / libc / sys / fsync.2

.\" Copyright (c) 1983 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	6.7 (Berkeley) 3/10/91
.\"
.Dd March 10, 1991
.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
.Nm
function call appeared in
.Bx 4.2 .
Commit	Line	Data
15637ed4 RG	1	.\" Copyright (c) 1983 The Regents of the University of California.
	2	.\" All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	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	.\" @(#)fsync.2 6.7 (Berkeley) 3/10/91
	33	.\"
	34	.Dd March 10, 1991
	35	.Dt FSYNC 2
	36	.Os BSD 4.2
	37	.Sh NAME
	38	.Nm fsync
	39	.Nd "synchronize a file's in-core state with that on disk"
	40	.Sh SYNOPSIS
	41	.Fd #include <unistd.h>
	42	.Ft int
	43	.Fn fsync "int fd"
	44	.Sh DESCRIPTION
	45	.Fn Fsync
	46	causes all modified data and attributes of
	47	.Fa fd
	48	to be moved to a permanent storage device.
	49	This normally results in all in-core modified copies
	50	of buffers for the associated file to be written to a disk.
	51	.Pp
	52	.Fn Fsync
	53	should be used by programs that require a file to be
	54	in a known state, for example, in building a simple transaction
	55	facility.
	56	.Sh RETURN VALUES
	57	A 0 value is returned on success. A -1 value indicates
	58	an error.
	59	.Sh ERRORS
	60	The
	61	.Fn fsync
	62	fails if:
	63	.Bl -tag -width Er
	64	.It Bq Er EBADF
65	.Fa Fd
66	is not a valid descriptor.
67	.It Bq Er EINVAL
68	.Fa Fd
69	refers to a socket, not to a file.
70	.It Bq Er EIO
71	An I/O error occurred while reading from or writing to the file system.
72	.El
73	.Sh SEE ALSO
74	.Xr sync 2 ,
75	.Xr sync 8 ,
76	.Xr update 8
77	.Sh HISTORY
78	The
79	.Nm
80	function call appeared in
81	.Bx 4.2 .