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UNGETWC(3) NetBSD Library Functions Manual UNGETWC(3)
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ungetwc -- un-get wide character from input stream
Standard C Library (libc, -lc)
ungetwc(wint_t wc, FILE *stream);
The ungetwc() function pushes the wide character wc (converted to an
wchar_t) back onto the input stream pointed to by stream. The pushed-
backed wide characters will be returned by subsequent reads on the stream
(in reverse order). A successful intervening call, using the same
stream, to one of the file positioning functions fseek(3), fsetpos(3), or
rewind(3) will discard the pushed back wide characters.
One wide character of push-back is guaranteed, but as long as there is
sufficient memory, an effectively infinite amount of pushback is allowed.
If a character is successfully pushed-back, the end-of-file indicator for
the stream is cleared.
The ungetwc() function returns the wide character pushed-back after the
conversion, or WEOF if the operation fails. If the value of the argument
c character equals WEOF, the operation will fail and the stream will
The ungetwc() function conforms to ISO/IEC 9899:1999 (``ISO C99'').
The current implementation uses a fixed sized ungetwc-buffer.
NetBSD 9.1 October 24, 2001 NetBSD 9.1