Index: libcfa/src/bits/containers.hfa
===================================================================
--- libcfa/src/bits/containers.hfa	(revision 6887a99bec2ddbf212ae4f78ceef36570bc08237)
+++ libcfa/src/bits/containers.hfa	(revision bd87a9ad8b09259bd23d09b16c0739c92a40d5f6)
@@ -9,7 +9,7 @@
 // Author           : Thierry Delisle
 // Created On       : Tue Oct 31 16:38:50 2017
-// Last Modified By : --
-// Last Modified On : --
-// Update Count     : 0
+// Last Modified By : Peter A. Buhr
+// Last Modified On : Wed Jun 26 08:52:20 2019
+// Update Count     : 4
 
 #pragma once
@@ -115,4 +115,9 @@
 		}
 		return top;
+	}
+
+	forall(dtype T | is_node(T))
+	static inline int ?!=?( const __stack(T) & this, __attribute__((unused)) zero_t zero ) {
+		return this.top != 0;
 	}
 #endif
@@ -186,5 +191,5 @@
 
 	forall(dtype T | is_node(T))
-	static inline bool ?!=?( __queue(T) & this, __attribute__((unused)) zero_t zero ) {
+	static inline int ?!=?( const __queue(T) & this, __attribute__((unused)) zero_t zero ) {
 		return this.head != 0;
 	}
@@ -268,5 +273,5 @@
 
 	forall(dtype T | sized(T))
-	static inline bool ?!=?( __dllist(T) & this, __attribute__((unused)) zero_t zero ) {
+	static inline int ?!=?( const __dllist(T) & this, __attribute__((unused)) zero_t zero ) {
 		return this.head != 0;
 	}