stdio/fflush.3

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  36 .\"     @(#)fflush.3    8.1 (Berkeley) 6/4/93
  37 .\" $FreeBSD: src/lib/libc/stdio/fflush.3,v 1.8 2001/10/01 16:08:59 ru Exp $
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  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
  55 The function
  56 .Fn fflush
  57 forces a write of all buffered data for the given output or update
  58 .Fa stream
  59 via the stream's underlying write function.
  60 The open status of the stream is unaffected.
  61 .Pp
  62 If the
  63 .Fa stream
  64 argument is
  65 .Dv NULL ,
  66 .Fn fflush
  67 flushes
  68 .Em all
  69 open output streams.
  70 .Pp
  71 The function
  72 .Fn fpurge
  73 erases any input or output buffered in the given
  74 .Fa stream .
  75 For output streams this discards any unwritten output.
  76 For input streams this discards any input read from the underlying object
  77 but not yet obtained via
  78 .Xr getc 3 ;
  79 this includes any text pushed back via
  80 .Xr ungetc .
  81 .Sh RETURN VALUES
  82 Upon successful completion 0 is returned.
  83 Otherwise,
  84 .Dv EOF
  85 is returned and the global variable
  86 .Va errno
  87 is set to indicate the error.
  88 .Sh ERRORS
  89 .Bl -tag -width Er
  90 .It Bq Er EBADF
  91 .Fa Stream
  92 is not an open stream, or, in the case of
  93 .Fn fflush ,
  94 not a stream open for writing.
  95 .El
  96 .Pp
  97 The function
  98 .Fn fflush
  99 may also fail and set
 100 .Va errno
 101 for 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
 109 The
 110 .Fn fflush
 111 function
 112 conforms to
 113 .St -isoC .