Restore time difference order so future extrapolation exceptions don'…

…t show non-sensical negative seconds into the future (#522)
ros · Feb 4, 2022 · c0cb44e · c0cb44e
1 parent 9fa9eec
commit c0cb44e
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/tf2/src/cache.cpp b/tf2/src/cache.cpp
@@ -76,7 +76,9 @@ void createExtrapolationException2(ros::Time t0, ros::Time t1, std::string* erro
 {
   if (error_str)
   {
-    ros::Duration tdiff = t1 - t0;
+    // Want this to come out positive, because this is a future extrapolation problem with t0
+    // t0 needs to come first because it will be bigger than t1
+    ros::Duration tdiff = t0 - t1;
     char str[163]; // Text without formatting strings has 102, each timestamp has up to 20
     snprintf(
         str, sizeof(str),