From 26cc1acbabc6e1485eb7dc9341b0242da15b2d6e Mon Sep 17 00:00:00 2001
From: Robert Lipe <robertlipe@gpsbabel.org>
Date: Tue, 19 Jul 2016 14:13:35 -0500
Subject: [PATCH] Issue error if interpolate filter has no routes or tracks to
 operate on.

---
 interpolate.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/interpolate.cc b/interpolate.cc
index 4c39be8c2..646c37476 100644
--- a/interpolate.cc
+++ b/interpolate.cc
@@ -74,6 +74,11 @@ interpfilt_process(void)
     track_backup(&count, &backuproute);
     route_flush_all_tracks();
   }
+
+  if (count == 0) {
+    fatal(MYNAME ": Found no routes or tracks to operate on.\n");
+  }
+
   QUEUE_FOR_EACH(backuproute, elem, tmp) {
     route_head* rte_old = (route_head*)elem;
 
-- 
2.30.2