diff --git a/sdk/head/atomic.h b/sdk/head/atomic.h
index 51c44bf..6574557 100644
--- a/sdk/head/atomic.h
+++ b/sdk/head/atomic.h
@@ -9,7 +9,7 @@
 #ifndef _SDK_ATOMIC_H_
 #define _SDK_ATOMIC_H_ 1
 
-#include <stdef.h>
+#include <ptdef.h>
 
 static inline ULONG
 AtomicAddLongNv(volatile ULONG *Ptr, ULONG Value)
diff --git a/sdk/head/bitops.h b/sdk/head/bitops.h
index c4209dd..f3c8821 100644
--- a/sdk/head/bitops.h
+++ b/sdk/head/bitops.h
@@ -9,7 +9,7 @@
 #ifndef _SDK_BITOPS_H_
 #define _SDK_BITOPS_H_ 1
 
-#include <stdef.h>
+#include <ptdef.h>
 
 #define BOPS_M1  0x5555555555555555ULL /* 01010101... */
 #define BOPS_M2  0x3333333333333333ULL /* 00110011... */