diff --git a/dlls/atl/atl30.c b/dlls/atl/atl30.c
index c2db138a503..29b29d4cbea 100644
--- a/dlls/atl/atl30.c
+++ b/dlls/atl/atl30.c
@@ -313,7 +313,7 @@ ATOM WINAPI AtlModuleRegisterWndClassInfoA(_ATL_MODULEA *pm, _ATL_WNDCLASSINFOA
 
         if (!wci->m_wc.lpszClassName)
         {
-            sprintf(wci->m_szAutoName, "ATL%08lx", (UINT_PTR)wci);
+            sprintf(wci->m_szAutoName, "ATL%08x", PtrToUint(wci));
             TRACE("auto-generated class name %s\n", wci->m_szAutoName);
             wci->m_wc.lpszClassName = wci->m_szAutoName;
         }
@@ -372,8 +372,8 @@ ATOM WINAPI AtlModuleRegisterWndClassInfoW(_ATL_MODULEW *pm, _ATL_WNDCLASSINFOW
 
         if (!wci->m_wc.lpszClassName)
         {
-            static const WCHAR szFormat[] = {'A','T','L','%','0','8','l','x',0};
-            swprintf(wci->m_szAutoName, ARRAY_SIZE(wci->m_szAutoName), szFormat, (UINT_PTR)wci);
+            static const WCHAR szFormat[] = {'A','T','L','%','0','8','x',0};
+            swprintf(wci->m_szAutoName, ARRAY_SIZE(wci->m_szAutoName), szFormat, PtrToUint(wci));
             TRACE("auto-generated class name %s\n", debugstr_w(wci->m_szAutoName));
             wci->m_wc.lpszClassName = wci->m_szAutoName;
         }