HP-UX Reference (11i v2 03/08) - 3 Library Functions N-Z (vol 7)

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ungetwc(3C) ungetwc(3C)

NAME

ungetwc(), ungetwc_unlocked() - push a wide character back into an input stream

SYNOPSIS

#include <wchar.h>

wint_t ungetwc(wint_t wc, FILE *stream);

Obsolescent Interface

wint_t ungetwc_unlocked(wint_t wc, FILE *stream);

Remarks

This function is compliant with the XPG4 Worldwide Portability Interface wide-character I/O functions.

It parallels the 8-bit character I/O function deﬁned in ungetc(3S).

DESCRIPTION

ungetwc() pushes the character corresponding to the wide-character code wc into the buffer associated

with an input stream. That wide-character code, wc, is returned by the next call to

getwc() (see

getwc(3C)) on that stream. A successful intervening call to a ﬁle positioning function with stream

(

fseek(), fsetpos(),orrewind()) erases all memory of the pushed-back characters.

ungetwc() affects only the buffer associated with the input stream . It does not affect the contents of the

ﬁle corresponding to stream .

One character of pushback is guaranteed.

If wc equals

WEOF, ungetwc() does nothing to the buffer and returns WEOF.

The deﬁnition for this function, the type

wint_t and the value WEOF are provided in the

<wchar.h>

header.

Obsolescent Interface

ungetwc_unlocked()

pushes a wide character back into an input stream.

APPLICATION USAGE

After

ungetwc() is applied to a stream, the stream becomes wide-oriented (see orientation (5)).

EXTERNAL INFLUENCES

Locale

The

LC_CTYPE category determines how wide character conversions are done.

International Code Set Support

Single- and multi-byte character code sets are supported.

RETURN VALUE

If successful,

ungetwc() and ungetwc_unlocked() return wc and clear the end-of-ﬁle indicator for

the stream. ungetwc() and ungetwc_unlocked() return WEOF if they cannot insert the wide char-

acter.

WARNINGS

ungetwc_unlocked() is an obsolescent interface supported only for compatibility with existing DCE

applications. New multithreaded applications should use ungetwc().

AUTHOR

ungetwc() and ungetwc_unlocked() were developed by OSF and HP.