man3/fclose.3

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.\"     @(#)fclose.3	6.7 (Berkeley) 6/29/91
.\"
.\" Converted for Linux, Mon Nov 29 15:19:14 1993, faith@cs.unc.edu
.\"
.\" Modified 2000-07-22 by Nicolás Lichtmaier <nick@debian.org>
.\"
.TH FCLOSE 3  2016-12-12 "GNU" "Linux Programmer's Manual"
.SH NAME
fclose \- close a stream
.SH SYNOPSIS
.B #include <stdio.h>
.PP
.BI "int fclose(FILE *" stream );
.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.
.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)).
.PP
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;
lb lb lb
l l l.
Interface	Attribute	Value
T{
.BR fclose ()
T}	Thread safety	MT-Safe
.TE
.SH CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C89, C99.
.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)