mbstowcs
size_t mbstowcs(wchar_t * __restrict , const char * __restrict, size_t);
if ((n = mbstowcs(NULL, str, 0)) == (size_t)-1)
if (mbstowcs(buf, str, n + 1) != n)
if (mbstowcs(m, (char*)tmp, len) ==
if ((n = mbstowcs(NULL, str, 0)) == (size_t)-1)
if (mbstowcs(buf, str, n + 1) != n)