man3/fclose.3

   1 .\" Copyright (c) 1990, 1991 The Regents of the University of California.
   2 .\" 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 .\" SPDX-License-Identifier: BSD-4-Clause-UC
   9 .\"
  10 .\"     @(#)fclose.3    6.7 (Berkeley) 6/29/91
  11 .\"
  12 .\" Converted for Linux, Mon Nov 29 15:19:14 1993, faith@cs.unc.edu
  13 .\"
  14 .\" Modified 2000-07-22 by Nicolás Lichtmaier <nick@debian.org>
  15 .\"
  16 .TH FCLOSE 3  2021-03-22 "Linux man-pages (unreleased)"
  17 .SH NAME
  18 fclose \- close a stream
  19 .SH LIBRARY
  20 Standard C library
  21 .RI ( libc ", " \-lc )
  22 .SH SYNOPSIS
  23 .nf
  24 .B #include <stdio.h>
  25 .PP
  26 .BI "int fclose(FILE *" stream );
  27 .fi
  28 .SH DESCRIPTION
  29 The
  30 .BR fclose ()
  31 function flushes the stream pointed to by
  32 .I stream
  33 (writing any buffered output data using
  34 .BR fflush (3))
  35 and closes the underlying file descriptor.
  36 .SH RETURN VALUE
  37 Upon successful completion, 0 is returned.
  38 Otherwise,
  39 .B EOF
  40 is returned and
  41 .I errno
  42 is set to indicate the error.
  43 In either case, any further access
  44 (including another call to
  45 .BR fclose ())
  46 to the stream results in undefined behavior.
  47 .SH ERRORS
  48 .TP
  49 .B EBADF
  50 The file descriptor underlying
  51 .I stream
  52 is not valid.
  53 .\"  This error cannot occur unless you are mixing ANSI C stdio operations and
  54 .\"  low-level file operations on the same stream. If you do get this error,
  55 .\"  you must have closed the stream's low-level file descriptor using
  56 .\"  something like close(fileno(stream)).
  57 .PP
  58 The
  59 .BR fclose ()
  60 function may also fail and set
  61 .I errno
  62 for any of the errors specified for the routines
  63 .BR close (2),
  64 .BR write (2),
  65 or
  66 .BR fflush (3).
  67 .SH ATTRIBUTES
  68 For an explanation of the terms used in this section, see
  69 .BR attributes (7).
  70 .ad l
  71 .nh
  72 .TS
  73 allbox;
  74 lbx lb lb
  75 l l l.
  76 Interface       Attribute       Value
  77 T{
  78 .BR fclose ()
  79 T}      Thread safety   MT-Safe
  80 .TE
  81 .hy
  82 .ad
  83 .sp 1
  84 .SH STANDARDS
  85 POSIX.1-2001, POSIX.1-2008, C89, C99.
  86 .SH NOTES
  87 Note that
  88 .BR fclose ()
  89 flushes only the user-space buffers provided by the
  90 C library.
  91 To ensure that the data is physically stored
  92 on disk the kernel buffers must be flushed too, for example, with
  93 .BR sync (2)
  94 or
  95 .BR fsync (2).
  96 .SH SEE ALSO
  97 .BR close (2),
  98 .BR fcloseall (3),
  99 .BR fflush (3),
 100 .BR fileno (3),
 101 .BR fopen (3),
 102 .BR setbuf (3)