man3/ungetwc.3

   1 .\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
   2 .\"
   3 .\" %%%LICENSE_START(GPLv2+_ONEPARA_DOC)
   4 .\" This is free documentation; you can redistribute it and/or
   5 .\" modify it under the terms of the GNU General Public License as
   6 .\" published by the Free Software Foundation; either version 2 of
   7 .\" the License, or (at your option) any later version.
   8 .\" %%%LICENSE_END
   9 .\"
  10 .\" References consulted:
  11 .\"   GNU glibc-2 source code and manual
  12 .\"   Dinkumware C library reference http://www.dinkumware.com/
  13 .\"   OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html
  14 .\"   ISO/IEC 9899:1999
  15 .\"
  16 .TH UNGETWC 3  1999-09-19 "GNU" "Linux Programmer's Manual"
  17 .SH NAME
  18 ungetwc \- push back a wide character onto a FILE stream
  19 .SH SYNOPSIS
  20 .nf
  21 .B #include <wchar.h>
  22 .sp
  23 .BI "wint_t ungetwc(wint_t " wc ", FILE *" stream );
  24 .fi
  25 .SH DESCRIPTION
  26 The
  27 .BR ungetwc ()
  28 function is the wide-character equivalent of the
  29 .BR ungetc (3)
  30 function.
  31 It pushes back a wide character onto \fIstream\fP and returns it.
  32 .PP
  33 If \fIwc\fP is \fBWEOF\fP, it returns \fBWEOF\fP.
  34 If \fIwc\fP is an invalid wide character,
  35 it sets \fIerrno\fP to \fBEILSEQ\fP and returns \fBWEOF\fP.
  36 .PP
  37 If \fIwc\fP is a valid wide character, it is pushed back onto the stream
  38 and thus becomes available for future wide-character read operations.
  39 The file-position indicator is decremented by one or more.
  40 The end-of-file
  41 indicator is cleared.
  42 The backing storage of the file is not affected.
  43 .PP
  44 Note: \fIwc\fP need not be the last wide-character read from the stream;
  45 it can be any other valid wide character.
  46 .PP
  47 If the implementation supports multiple push-back operations in a row, the
  48 pushed-back wide characters will be read in reverse order; however, only one
  49 level of push-back is guaranteed.
  50 .SH RETURN VALUE
  51 The
  52 .BR ungetwc ()
  53 function returns \fIwc\fP when successful, or \fBWEOF\fP upon
  54 failure.
  55 .SH CONFORMING TO
  56 C99.
  57 .SH NOTES
  58 The behavior of
  59 .BR ungetwc ()
  60 depends on the
  61 .B LC_CTYPE
  62 category of the
  63 current locale.
  64 .SH SEE ALSO
  65 .BR fgetwc (3)