(END_NODE): New macro.

(relation_node): Now unsigned int, not short int.

diff --git a/src/relation.h b/src/relation.h
index f79174c2487f744863f746c21eabefc3130cd5e5..1c461f6019d922fb588d0d0b8efed56812f62631 100644 (file)
--- a/src/relation.h
+++ b/src/relation.h
@@ -25,9 +25,11 @@
 /* Performing operations on graphs coded as list of adjacency.
 
    If GRAPH is a relation, then GRAPH[Node] is a list of adjacent
-   nodes, ended with -1.  */
+   nodes, ended with END_NODE.  */
 
-typedef short int relation_node;
+#define END_NODE ((relation_node) -1)
+
+typedef unsigned int relation_node;
 typedef relation_node *relation_nodes;
 typedef relation_nodes *relation;