diff --git a/sdk/xtdk/rtltypes.h b/sdk/xtdk/rtltypes.h
index abde6ea..d3fe726 100644
--- a/sdk/xtdk/rtltypes.h
+++ b/sdk/xtdk/rtltypes.h
@@ -9,6 +9,7 @@
 #ifndef __XTDK_RTLTYPES_H
 #define __XTDK_RTLTYPES_H
 
+#include <xtbase.h>
 #include <xttypes.h>
 
 
@@ -16,4 +17,17 @@
 #define GUID_STRING_LENGTH              38
 #define PARTUUID_STRING_LENGTH          13
 
+/* Runtime Library routine callbacks */
+typedef VOID (*PWRITE_CHARACTER)(IN CHAR Character);
+typedef VOID (*PWRITE_WIDE_CHARACTER)(IN WCHAR Character);
+
+/* Runtime Library print context structure definition */
+typedef struct _RTL_PRINT_CONTEXT
+{
+    PWRITE_CHARACTER WriteCharacter;
+    PWRITE_WIDE_CHARACTER WriteWideCharacter;
+    ULONG CharactersWritten;
+    ULONG Limit;
+} RTL_PRINT_CONTEXT, *PRTL_PRINT_CONTEXT;
+
 #endif /* __XTDK_RTLTYPES_H */