UNGETWC(3) | Library Functions Manual | UNGETWC(3)

# NAME

`ungetwc` — un-get wide character from input stream

# 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 a 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), ungetc(3)

# STANDARDS

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

# BUGS

The current implementation uses a fixed sized ungetwc-buffer.

February 2, 2021 | Debian