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.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" @(#)fflush.3 8.1 (Berkeley) 6/4/93 37.\" $FreeBSD$ 38.\" 39.Dd June 4, 1993 40.Dt FFLUSH 3 41.Os 42.Sh NAME 43.Nm fflush , 44.Nm fpurge 45.Nd flush a stream 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.In stdio.h 50.Ft int 51.Fn fflush "FILE *stream" 52.Ft int 53.Fn fpurge "FILE *stream" 54.Sh DESCRIPTION 55The function 56.Fn fflush 57forces a write of all buffered data for the given output or update 58.Fa stream 59via the stream's underlying write function. 60The open status of the stream is unaffected. 61.Pp 62If the 63.Fa stream 64argument is 65.Dv NULL , 66.Fn fflush 67flushes 68.Em all 69open output streams. 70.Pp 71The function 72.Fn fpurge 73erases any input or output buffered in the given 74.Fa stream . 75For output streams this discards any unwritten output. 76For input streams this discards any input read from the underlying object 77but not yet obtained via 78.Xr getc 3 ; 79this includes any text pushed back via 80.Xr ungetc . 81.Sh RETURN VALUES 82Upon successful completion 0 is returned. 83Otherwise, 84.Dv EOF 85is returned and the global variable 86.Va errno 87is set to indicate the error. 88.Sh ERRORS 89.Bl -tag -width Er 90.It Bq Er EBADF 91.Fa Stream 92is not an open stream, or, in the case of 93.Fn fflush , 94not a stream open for writing. 95.El 96.Pp 97The function 98.Fn fflush 99may also fail and set 100.Va errno 101for any of the errors specified for the routine 102.Xr write 2 . 103.Sh SEE ALSO 104.Xr write 2 , 105.Xr fclose 3 , 106.Xr fopen 3 , 107.Xr setbuf 3 108.Sh STANDARDS 109The 110.Fn fflush 111function 112conforms to 113.St -isoC . 114