1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
|
'\" t
.\" Copyright 1990-1991, The Regents of the University of California.
.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: BSD-4-Clause-UC
.\"
.TH fclose 3 2025-05-17 "Linux man-pages (unreleased)"
.SH NAME
fclose \- close a stream
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.B #include <stdio.h>
.P
.BI "int fclose(FILE *" stream );
.fi
.SH DESCRIPTION
The
.BR fclose ()
function flushes the stream pointed to by
.I stream
(writing any buffered output data using
.BR fflush (3))
and closes the underlying file descriptor.
.\" Reviewed by upstream and rejected, May 2012, Debian#67239
.PP
The behaviour of
.BR fclose ()
is undefined if the
.I stream
parameter is an illegal pointer, or is a descriptor already passed
to a previous invocation of
.BR fclose ().
.\" End of patch
.SH RETURN VALUE
Upon successful completion, 0 is returned.
Otherwise,
.B EOF
is returned and
.I errno
is set to indicate the error.
In either case, any further access
(including another call to
.BR fclose ())
to the stream results in undefined behavior.
.SH ERRORS
.TP
.B EBADF
The file descriptor underlying
.I stream
is not valid.
.\" This error cannot occur unless you are mixing ANSI C stdio operations and
.\" low-level file operations on the same stream. If you do get this error,
.\" you must have closed the stream's low-level file descriptor using
.\" something like close(fileno(stream)).
.P
The
.BR fclose ()
function may also fail and set
.I errno
for any of the errors specified for the routines
.BR close (2),
.BR write (2),
or
.BR fflush (3).
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbx lb lb
l l l.
Interface Attribute Value
T{
.na
.nh
.BR fclose ()
T} Thread safety MT-Safe
.TE
.SH STANDARDS
C11, POSIX.1-2008.
.SH HISTORY
C89, POSIX.1-2001.
.SH NOTES
Note that
.BR fclose ()
flushes only the user-space buffers provided by the
C library.
To ensure that the data is physically stored
on disk the kernel buffers must be flushed too, for example, with
.BR sync (2)
or
.BR fsync (2).
.SH SEE ALSO
.BR close (2),
.BR fcloseall (3),
.BR fflush (3),
.BR fileno (3),
.BR fopen (3),
.BR setbuf (3)
|
