diff --git a/server/class.c b/server/class.c
index 334542e..ae594df 100644
--- a/server/class.c
+++ b/server/class.c
@@ -142,11 +142,13 @@
 DECL_HANDLER(create_class)
 {
     struct window_class *class;
+    struct unicode_str name;
     atom_t atom;
 
-    if (get_req_data_size())
+    get_req_unicode_str( &name );
+    if (name.len)
     {
-        atom = add_global_atom( NULL, get_req_data(), get_req_data_size() / sizeof(WCHAR) );
+        atom = add_global_atom( NULL, &name );
         if (!atom) return;
     }
     else
@@ -187,10 +189,11 @@
 DECL_HANDLER(destroy_class)
 {
     struct window_class *class;
+    struct unicode_str name;
     atom_t atom = req->atom;
 
-    if (get_req_data_size())
-        atom = find_global_atom( NULL, get_req_data(), get_req_data_size() / sizeof(WCHAR) );
+    get_req_unicode_str( &name );
+    if (name.len) atom = find_global_atom( NULL, &name );
 
     if (!(class = find_class( current->process, atom, req->instance )))
         set_win32_error( ERROR_CLASS_DOES_NOT_EXIST );