HP-UX Reference (11i v2 07/12) - 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
Environment Variables
LC_CTYPE determines how wide-character conversions are done.
International Code Set Support
Single- and multibyte 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.
SEE ALSO
flockfile(3S), fseek(3S), fgetpos(3S), getwc(3C), setbuf(3S), orientation(5), thread_safety(5).
STANDARDS CONFORMANCE
ungetwc(): XPG4
HP-UX 11i Version 2: December 2007 Update − 1 − Hewlett-Packard Company 575