diff --git a/include/private-include/dollop.h b/include/private-include/dollop.h
index b5bbc2f80bd601caf9e4e778c3ac72609d8e1c1d..a5d2be8c986dd0be510c2613336b0af3698f498f 100644
--- a/include/private-include/dollop.h
+++ b/include/private-include/dollop.h
@@ -57,8 +57,8 @@ namespace Zipr_SDK
 			virtual Dollop_t*      getTargetDollop()   const = 0 ; 
 			virtual Dollop_t*      getMemberOfDollop() const = 0 ; 
 
-			virtual bool operator==(const DollopEntry_t &);
-			virtual bool operator!=(const DollopEntry_t &);
+			virtual bool operator==(const DollopEntry_t &) const;
+			virtual bool operator!=(const DollopEntry_t &) const;
 
 		friend ostream &operator<<(ostream &, const DollopEntry_t &);
 	};