if (!wci->m_wc.lpszClassName)
{
static const WCHAR szFormat[] = {'A','T','L','%','0','8','l','x',0};
- snprintfW(wci->m_szAutoName, sizeof(wci->m_szAutoName)/sizeof(WCHAR), szFormat, (UINT_PTR)wci);
+ snprintfW(wci->m_szAutoName, ARRAY_SIZE(wci->m_szAutoName), szFormat, (UINT_PTR)wci);
TRACE("auto-generated class name %s\n", debugstr_w(wci->m_szAutoName));
wci->m_wc.lpszClassName = wci->m_szAutoName;
}