The <STRONG>unget_wch</STRONG> function pushes the wide character <EM>wch</EM> back onto the head
of the input queue, so the wide character is returned by the next call
to <STRONG>get_wch</STRONG>. The pushback of one character is guaranteed. If the pro-
gram calls <STRONG>unget_wch</STRONG> too many times without an intervening call to
<STRONG>get_wch</STRONG>, the operation may fail.
The <STRONG>unget_wch</STRONG> function pushes the wide character <EM>wch</EM> back onto the head
of the input queue, so the wide character is returned by the next call
to <STRONG>get_wch</STRONG>. The pushback of one character is guaranteed. If the pro-
gram calls <STRONG>unget_wch</STRONG> too many times without an intervening call to
<STRONG>get_wch</STRONG>, the operation may fail.