.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>

.\"

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.\" References consulted:

.\"   GNU glibc-2 source code and manual

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.\"   OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html

.\"   ISO/IEC 9899:1999

.\"

.TH UNGETWC 3  2015-08-08 "GNU" "Linux Programmer's Manual"

.SH NAME

ungetwc \- push back a wide character onto a FILE stream

.SH SYNOPSIS

.nf

.B #include <wchar.h>

.PP

.BI "wint_t ungetwc(wint_t " wc ", FILE *" stream );

.fi

.SH DESCRIPTION

The

.BR ungetwc ()

function is the wide-character equivalent of the

.BR ungetc (3)

function.

It pushes back a wide character onto

.I stream

and returns it.

.PP

If

.I wc

is

.BR WEOF ,

it returns

.BR WEOF .

If

.I wc

is an invalid wide character,

it sets

.IR errno

to

.B EILSEQ

and returns

.BR WEOF .

.PP

If

.I wc

is a valid wide character, it is pushed back onto the stream

and thus becomes available for future wide-character read operations.

The file-position indicator is decremented by one or more.

The end-of-file

indicator is cleared.

The backing storage of the file is not affected.

.PP

Note:

.I wc

need not be the last wide-character read from the stream;

it can be any other valid wide character.

.PP

If the implementation supports multiple push-back operations in a row, the

pushed-back wide characters will be read in reverse order; however, only one

level of push-back is guaranteed.

.SH RETURN VALUE

The

.BR ungetwc ()

function returns

.IR wc

when successful, or

.B WEOF

upon

failure.

.SH ATTRIBUTES

For an explanation of the terms used in this section, see

.BR attributes (7).

.TS

allbox;

lb lb lb

l l l.

Interface	Attribute	Value

T{

.BR ungetwc ()

T}	Thread safety	MT-Safe

.TE

.SH CONFORMING TO

POSIX.1-2001, POSIX.1-2008, C99.

.SH NOTES

The behavior of

.BR ungetwc ()

depends on the

.B LC_CTYPE

category of the

current locale.

.SH SEE ALSO

.BR fgetwc (3)

.SH COLOPHON

This page is part of release 4.15 of the Linux

.I man-pages

project.

A description of the project,

information about reporting bugs,

and the latest version of this page,

can be found at

\%https://www.kernel.org/doc/man\-pages/.