1.\" $NetBSD: fflush.3,v 1.4 1995/02/02 01:15:36 jtc 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. All advertising materials mentioning features or use of this software 19.\" must display the following acknowledgement: 20.\" This product includes software developed by the University of 21.\" California, Berkeley and its contributors. 22.\" 4. Neither the name of the University nor the names of its contributors 23.\" may be used to endorse or promote products derived from this software 24.\" without specific prior written permission. 25.\" 26.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36.\" SUCH DAMAGE. 37.\" 38.\" @(#)fflush.3 8.1 (Berkeley) 6/4/93 39.\" 40.Dd June 4, 1993 41.Dt FFLUSH 3 42.Os 43.Sh NAME 44.Nm fflush , 45.Nm fpurge 46.Nd flush a stream 47.Sh SYNOPSIS 48.Fd #include <stdio.h> 49.Ft int 50.Fn fflush "FILE *stream" 51.Ft int 52.Fn fpurge "FILE *stream" 53.Sh DESCRIPTION 54The function 55.Fn fflush 56forces a write of all buffered data for the given output or update 57.Fa stream 58via the stream's underlying write function. 59The open status of the stream is unaffected. 60.Pp 61If the 62.Fa stream 63argument is 64.Dv NULL , 65.Fn fflush 66flushes 67.Em all 68open output streams. 69.Pp 70The function 71.Fn fpurge 72erases any input or output buffered in the given 73.Fa stream . 74For output streams this discards any unwritten output. 75For input streams this discards any input read from the underlying object 76but not yet obtained via 77.Xr getc 3 ; 78this includes any text pushed back via 79.Xr ungetc . 80.Sh RETURN VALUES 81Upon successful completion 0 is returned. 82Otherwise, 83.Dv EOF 84is returned and the global variable 85.Va errno 86is set to indicate the error. 87.Sh ERRORS 88.Bl -tag -width Er 89.It Bq Er EBADF 90.Fa Stream 91is not an open stream, or, in the case of 92.Fn fflush , 93not a stream open for writing. 94.El 95.Pp 96The function 97.Fn fflush 98may also fail and set 99.Va errno 100for any of the errors specified for the routine 101.Xr write 2 . 102.Sh SEE ALSO 103.Xr write 2 , 104.Xr fopen 3 , 105.Xr fclose 3 , 106.Xr setbuf 3 107.Sh STANDARDS 108The 109.Fn fflush 110function 111conforms to 112.St -ansiC . 113