1*2fe8fb19SBen Gras.\" $NetBSD: fdatasync.2,v 1.16 2008/04/30 13:10:51 martin Exp $ 2*2fe8fb19SBen Gras.\" 3*2fe8fb19SBen Gras.\" Copyright (c) 1998 The NetBSD Foundation, Inc. 4*2fe8fb19SBen Gras.\" All rights reserved. 5*2fe8fb19SBen Gras.\" 6*2fe8fb19SBen Gras.\" This code is derived from software contributed to The NetBSD Foundation 7*2fe8fb19SBen Gras.\" by Klaus Klein. 8*2fe8fb19SBen Gras.\" 9*2fe8fb19SBen Gras.\" Redistribution and use in source and binary forms, with or without 10*2fe8fb19SBen Gras.\" modification, are permitted provided that the following conditions 11*2fe8fb19SBen Gras.\" are met: 12*2fe8fb19SBen Gras.\" 1. Redistributions of source code must retain the above copyright 13*2fe8fb19SBen Gras.\" notice, this list of conditions and the following disclaimer. 14*2fe8fb19SBen Gras.\" 2. Redistributions in binary form must reproduce the above copyright 15*2fe8fb19SBen Gras.\" notice, this list of conditions and the following disclaimer in the 16*2fe8fb19SBen Gras.\" documentation and/or other materials provided with the distribution. 17*2fe8fb19SBen Gras.\" 18*2fe8fb19SBen Gras.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19*2fe8fb19SBen Gras.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20*2fe8fb19SBen Gras.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21*2fe8fb19SBen Gras.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22*2fe8fb19SBen Gras.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23*2fe8fb19SBen Gras.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24*2fe8fb19SBen Gras.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25*2fe8fb19SBen Gras.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26*2fe8fb19SBen Gras.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27*2fe8fb19SBen Gras.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28*2fe8fb19SBen Gras.\" POSSIBILITY OF SUCH DAMAGE. 29*2fe8fb19SBen Gras.\" 30*2fe8fb19SBen Gras.Dd October 25, 2003 31*2fe8fb19SBen Gras.Dt FDATASYNC 2 32*2fe8fb19SBen Gras.Os 33*2fe8fb19SBen Gras.Sh NAME 34*2fe8fb19SBen Gras.Nm fdatasync 35*2fe8fb19SBen Gras.Nd synchronize the data of a file 36*2fe8fb19SBen Gras.Sh LIBRARY 37*2fe8fb19SBen Gras.Lb libc 38*2fe8fb19SBen Gras.Sh SYNOPSIS 39*2fe8fb19SBen Gras.In unistd.h 40*2fe8fb19SBen Gras.Ft int 41*2fe8fb19SBen Gras.Fn fdatasync "int fd" 42*2fe8fb19SBen Gras.Sh DESCRIPTION 43*2fe8fb19SBen GrasThe 44*2fe8fb19SBen Gras.Fn fdatasync 45*2fe8fb19SBen Grasfunction forces all modified data associated with the file descriptor 46*2fe8fb19SBen Gras.Fa fd 47*2fe8fb19SBen Grasto be flushed to stable storage. 48*2fe8fb19SBen Gras.Pp 49*2fe8fb19SBen GrasThe functionality is as described for 50*2fe8fb19SBen Gras.Xr fsync 2 , 51*2fe8fb19SBen Graswith the exception that file status information need not be synchronized, 52*2fe8fb19SBen Graswhich may result in a performance gain, compared to 53*2fe8fb19SBen Gras.Xr fsync 2 . 54*2fe8fb19SBen GrasThis behaviour is commonly known as 55*2fe8fb19SBen Gras.Bf -symbolic 56*2fe8fb19SBen Grassynchronized I/O data integrity completion. 57*2fe8fb19SBen Gras.Ef 58*2fe8fb19SBen Gras.Sh RETURN VALUES 59*2fe8fb19SBen GrasA value of 0 is returned on success. 60*2fe8fb19SBen GrasOtherwise, a value \-1 is returned and 61*2fe8fb19SBen Gras.Va errno 62*2fe8fb19SBen Grasis set to indicate the error. 63*2fe8fb19SBen Gras.Sh ERRORS 64*2fe8fb19SBen GrasThe 65*2fe8fb19SBen Gras.Fn fdatasync 66*2fe8fb19SBen Grasfunction will fail if: 67*2fe8fb19SBen Gras.Bl -tag -width Er 68*2fe8fb19SBen Gras.It Bq Er EBADF 69*2fe8fb19SBen GrasThe 70*2fe8fb19SBen Gras.Fa fd 71*2fe8fb19SBen Grasargument is not a valid file descriptor open for writing. 72*2fe8fb19SBen Gras.It Bq Er EINVAL 73*2fe8fb19SBen GrasThis implementation does not support synchronized I/O for this file. 74*2fe8fb19SBen Gras.It Bq Er ENOSYS 75*2fe8fb19SBen GrasThe 76*2fe8fb19SBen Gras.Fn fdatasync 77*2fe8fb19SBen Grasfunction is not supported by this implementation. 78*2fe8fb19SBen Gras.El 79*2fe8fb19SBen Gras.Pp 80*2fe8fb19SBen GrasIn the event that any of the I/O operations to be performed fail, 81*2fe8fb19SBen Gras.Fn fdatasync 82*2fe8fb19SBen Grasreturns the error conditions defined for 83*2fe8fb19SBen Gras.Xr read 2 84*2fe8fb19SBen Grasand 85*2fe8fb19SBen Gras.Xr write 2 , 86*2fe8fb19SBen Grasand outstanding I/O operations are not guaranteed to have been completed. 87*2fe8fb19SBen Gras.Sh SEE ALSO 88*2fe8fb19SBen Gras.Xr fsync 2 , 89*2fe8fb19SBen Gras.Xr open 2 , 90*2fe8fb19SBen Gras.Xr read 2 , 91*2fe8fb19SBen Gras.Xr write 2 92*2fe8fb19SBen Gras.Sh STANDARDS 93*2fe8fb19SBen GrasThe 94*2fe8fb19SBen Gras.Fn fdatasync 95*2fe8fb19SBen Grasfunction conforms to 96*2fe8fb19SBen Gras.St -p1003.1b-93 . 97