diff --git a/xtoskrnl/rtl/plist.c b/xtoskrnl/rtl/plist.c
index 57215f5..d1bc624 100644
--- a/xtoskrnl/rtl/plist.c
+++ b/xtoskrnl/rtl/plist.c
@@ -100,7 +100,7 @@ RtlInsertTailList(IN OUT PLIST_ENTRY ListHead,
  * @since XT 1.0
  */
 BOOLEAN
-RtlListEmpty(PLIST_ENTRY ListHead)
+RtlListEmpty(IN PLIST_ENTRY ListHead)
 {
     return (ListHead->Flink == ListHead);
 }
@@ -116,7 +116,7 @@ RtlListEmpty(PLIST_ENTRY ListHead)
  * @since XT 1.0
  */
 BOOLEAN
-RtlListLoop(PLIST_ENTRY ListHead)
+RtlListLoop(IN PLIST_ENTRY ListHead)
 {
     PLIST_ENTRY SlowEntry, FastEntry;
 
diff --git a/xtoskrnl/rtl/widestr.c b/xtoskrnl/rtl/widestr.c
index 458dd99..c5a16f9 100644
--- a/xtoskrnl/rtl/widestr.c
+++ b/xtoskrnl/rtl/widestr.c
@@ -79,9 +79,9 @@ RtlWideStringCompare(IN CONST PWCHAR String1,
  */
 XTCDECL
 PWCHAR
-RtlWideStringConcatenate(PWCHAR Destination,
-                         PWCHAR Source,
-                         SIZE_T Count)
+RtlWideStringConcatenate(OUT PWCHAR Destination,
+                         IN PWCHAR Source,
+                         IN SIZE_T Count)
 {
     PWCHAR DestString = Destination;