diff --git a/logger/timeline.h b/logger/timeline.h
index 4d8283a9045f79e5a2a66d7e2e0d0dc129362b0f..a0fed57f6b2bf98beb6907e0d4800e068c5d0096 100644
--- a/logger/timeline.h
+++ b/logger/timeline.h
@@ -8,10 +8,19 @@ typedef char timebin_t;
 typedef long long integertime_t;
 
 struct time_array {
+  /* Pointer to next element */
   void *next;
+
+  /* Pointer to prev element */
   void *prev;
+
+  /* Integertime of this timestamp */
   integertime_t timestamp;
+
+  /* Double time of this timestamp */
   double time;
+
+  /* Offset in the file of this timestamp */
   size_t offset;
 };