man3/fpurge.3

   1 .\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>.
   2 .\"
   3 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   4 .\"
   5 .TH FPURGE 3 2021-03-22 GNU "Linux Programmer's Manual"
   6 .SH NAME
   7 fpurge, __fpurge \- purge a stream
   8 .SH LIBRARY
   9 Standard C library
  10 .RI ( libc ", " \-lc )
  11 .SH SYNOPSIS
  12 .nf
  13 /* unsupported */
  14 .B #include <stdio.h>
  15 .PP
  16 .BI "int fpurge(FILE *" stream );
  17 .PP
  18 /* supported */
  19 .B #include <stdio.h>
  20 .B #include <stdio_ext.h>
  21 .PP
  22 .BI "void  __fpurge(FILE *" stream );
  23 .fi
  24 .SH DESCRIPTION
  25 The function
  26 .BR fpurge ()
  27 clears the buffers of the given stream.
  28 For output streams this discards any unwritten output.
  29 For input streams this discards any input read from the underlying object
  30 but not yet obtained via
  31 .BR getc (3);
  32 this includes any text pushed back via
  33 .BR ungetc (3).
  34 See also
  35 .BR fflush (3).
  36 .PP
  37 The function
  38 .BR __fpurge ()
  39 does precisely the same, but without returning a value.
  40 .SH RETURN VALUE
  41 Upon successful completion
  42 .BR fpurge ()
  43 returns 0.
  44 On error, it returns \-1 and sets
  45 .I errno
  46 to indicate the error.
  47 .SH ERRORS
  48 .TP
  49 .B EBADF
  50 .I stream
  51 is not an open stream.
  52 .SH ATTRIBUTES
  53 For an explanation of the terms used in this section, see
  54 .BR attributes (7).
  55 .ad l
  56 .nh
  57 .TS
  58 allbox;
  59 lbx lb lb
  60 l l l.
  61 Interface       Attribute       Value
  62 T{
  63 .BR __fpurge ()
  64 T}      Thread safety   MT-Safe race:stream
  65 .TE
  66 .hy
  67 .ad
  68 .sp 1
  69 .SH CONFORMING TO
  70 These functions are nonstandard and not portable.
  71 The function
  72 .BR fpurge ()
  73 was introduced in 4.4BSD and is not available under Linux.
  74 The function
  75 .BR __fpurge ()
  76 was introduced in Solaris, and is present in glibc 2.1.95 and later.
  77 .SH NOTES
  78 Usually it is a mistake to want to discard input buffers.
  79 .SH SEE ALSO
  80 .\" .BR fclean (3),
  81 .BR fflush (3),
  82 .BR setbuf (3),
  83 .BR stdio_ext (3)