WCSSIZE
len = wcsftime(wcs, WCSSIZE, wfmt, &sample_tm);
wchar_t wfmt[WCSSIZE];
wchar_t wcs[WCSSIZE];
if (mbstowcs_l(wfmt, "%B", WCSSIZE, loc) == (size_t)-1) {
len = wcsftime_l(wcs, WCSSIZE, wfmt, &sample_tm, loc);
wchar_t wcs[WCSSIZE];
len = wcsftime(wcs, WCSSIZE, "%B", &sample_tm);