man3/ungetwc.3

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