UNGETWC(3) |
Library Functions Manual |
UNGETWC(3) |
NAME
ungetwc — un-get wide character from input stream
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdio.h>
#include <wchar.h>
wint_t
ungetwc(wint_t wc, FILE *stream);
DESCRIPTION
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.
RETURN VALUES
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 remain unchanged.
STANDARDS
The ungetwc() function conforms to ISO/IEC 9899:1999 (“ISO C99”).
BUGS
The current implementation uses a fixed sized ungetwc-buffer.