diff --git a/src/LinearMath/btHashMap.h b/src/LinearMath/btHashMap.h
index a0a062750..5e9cdb605 100644
--- a/src/LinearMath/btHashMap.h
+++ b/src/LinearMath/btHashMap.h
@@ -52,7 +52,7 @@ struct btHashString
 	{
 			int ret = 0 ;
 
-			while( ! (ret = *(unsigned char *)src - *(unsigned char *)dst) && *dst)
+			while( ! (ret = *(const unsigned char *)src - *(const unsigned char *)dst) && *dst)
 					++src, ++dst;
 
 			if ( ret < 0 )