diff --git a/public/tier1/utlbuffer.h b/public/tier1/utlbuffer.h
index 5e8dd616..795db8f3 100644
--- a/public/tier1/utlbuffer.h
+++ b/public/tier1/utlbuffer.h
@@ -471,8 +471,17 @@ protected:
 	int m_nOffset;
 
 	UtlBufferOverflowFunc_t m_GetOverflowFunc;
+
+#ifdef PLATFORM_POSIX
+    void* m_OverFlowFunc2;
+#endif
+
 	UtlBufferOverflowFunc_t m_PutOverflowFunc;
 
+#ifdef PLATFORM_POSIX
+    void* m_OverFlowFunc4;
+#endif
+
 	CByteswap	m_Byteswap;
 };
 
@@ -1400,3 +1409,4 @@ inline void CUtlBuffer::Spew( )
 
 #endif // UTLBUFFER_H
 
+