October 24, 2001 UNGETWC 3

### NAME

ungetwc - un-get wide-character from input stream

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```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.

### SEE ALSO

fseek(3), getwc(3)

### STANDARDS

The ungetwc(``) function conforms to ISO/IEC 9899:1999 (``ISO C99'') .

### BUGS

The current implementation uses a fixed sized ungetwc-buffer.