ungetwc

Defined in header <wchar.h>
wint_t ungetwc ( wint_t ch, FILE * stream ) ;		(since C95)

If ch does not equal WEOF , pushes the wide character ch into the input buffer associated with the stream stream in such a manner that subsequent read operation from stream will retrieve that wide character. The external device associated with the stream is not modified.

Stream repositioning operations fseek , fsetpos , and rewind discard the effects of ungetwc .

If ungetwc is called more than once without an intervening read or repositioning, it may fail (in other words, a pushback buffer of size 1 is guaranteed, but any larger buffer is implementation-defined). If multiple successful ungetwc were performed, read operations retrieve the pushed-back wide characters in reverse order of ungetwc

If ch equals WEOF , the operation fails and the stream is not affected.

A successful call to ungetwc clears the end of file status flag feof .

A successful call to ungetwc on a stream (whether text or binary) modifies the stream position indicator in unspecified manner but guarantees that after all pushed-back wide characters are retrieved with a read operation, the stream position indicator is equal to its value before ungetwc .

Parameters

ch	-	wide character to be put back
stream	-	file stream to put the wide character back to

Return value

On success ch is returned.

On failure WEOF is returned and the given stream remains unchanged.

References