Import Geant4 11.2.0 source tree

source/event/include/G4UserEventAction.hh

@@ -38,6 +38,7 @@
 // the G4VUserPrimaryGeneratorAction concrete class
 
 // Author: Makoto Asai (SLAC)
+// Adding MergeSubEvent - Sep/11/2023 Makoto Asai (JLab)
 // --------------------------------------------------------------------
 #ifndef G4UserEventAction_hh
 #define G4UserEventAction_hh 1
@@ -57,6 +58,16 @@ class G4UserEventAction
     virtual void EndOfEventAction(const G4Event* anEvent);
       // Two virtual method the user can override.
 
+    virtual void MergeSubEvent(G4Event* masterEvent, const G4Event* subEvent);
+      // A virtual method to merge the results of a sub-event into the master
+      // event. The ownership of "subEvent" and its contents blong to the
+      // worker thread. 
+      // Merging trajectories and scores are taken care by G4Event and
+      // G4ScoringManager so the user does not need to take care of them.
+      // But merging hits collections and UserEventInformation must be taken 
+      // care by this method.
+      // This method is invoked only for the case of sub-event parallelism.
+
   protected:
 
       G4EventManager* fpEventManager = nullptr; // not owned