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: head/lib/libc/stdio/fflush.3 108087 2002-12-19 09:40:28Z ru $
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
91The
92.Fa stream
93argument
94is not an open stream, or, in the case of
95.Fn fflush ,
96not a stream open for writing.
97.El
98.Pp
99The function
100.Fn fflush
101may also fail and set
102.Va errno
103for any of the errors specified for the routine
104.Xr write 2 .
105.Sh SEE ALSO
106.Xr write 2 ,
107.Xr fclose 3 ,
108.Xr fopen 3 ,
109.Xr setbuf 3
110.Sh STANDARDS
111The
112.Fn fflush
113function
114conforms to
115.St -isoC .
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: head/lib/libc/stdio/fflush.3 108087 2002-12-19 09:40:28Z ru $
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
91The
92.Fa stream
93argument
94is not an open stream, or, in the case of
95.Fn fflush ,
96not a stream open for writing.
97.El
98.Pp
99The function
100.Fn fflush
101may also fail and set
102.Va errno
103for any of the errors specified for the routine
104.Xr write 2 .
105.Sh SEE ALSO
106.Xr write 2 ,
107.Xr fclose 3 ,
108.Xr fopen 3 ,
109.Xr setbuf 3
110.Sh STANDARDS
111The
112.Fn fflush
113function
114conforms to
115.St -isoC .