wcrtomb
extern size_t wcrtomb(char *_RESTRICT_KYWD, wchar_t,
using std::wcrtomb;
n = wcrtomb(bracket, ch, &mbs);
clen = wcrtomb(buf, OPND(s), &mbs);
clen = wcrtomb(cp, OPND(s), &mbs);
if ((mb_len = wcrtomb((char *) wio->_mb, wc, &wio->_state)) < 0)
j = wcrtomb(mb, cc->_wc[i], &__m_screen->_state);