Add ppq_insert() return codes + fix breadth_first_search_4dir()

1 files changed, 3 insertions, 0 deletions

diff --git a/priority_queue.h b/priority_queue.h
index 63e9bbc..13eea1a 100644
--- a/priority_queue.h
+++ b/priority_queue.h
@@ -19,6 +19,9 @@ typedef struct PositionPQNode_s PositionPQ;
 PositionPQ *ppq_new(Position pos, size_t priority);
 
 /* Insert a pos with priority into a given PositionPQ */
+#define PPQ_INSERT_SUCCESS 0
+#define PPQ_INSERT_NEW 1 /* ppq was NULL, created a new one */
+#define PPQ_INSERT_ALREADY 2 /* pos is already in ppq */
 int ppq_insert(PositionPQ **ppq, Position pos, size_t priority);
 
 /* Remove and return the position with the lowest priority */