From d6e83c7257e124027f010d09aa196077888219ef Mon Sep 17 00:00:00 2001
From: Fred Suter <suterf@ornl.gov>
Date: Wed, 31 May 2023 10:10:41 -0400
Subject: [PATCH] improve comment

---
 include/simgrid/s4u/Comm.hpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/simgrid/s4u/Comm.hpp b/include/simgrid/s4u/Comm.hpp
index 2577c88845..3091cdd7f5 100644
--- a/include/simgrid/s4u/Comm.hpp
+++ b/include/simgrid/s4u/Comm.hpp
@@ -44,7 +44,11 @@ protected:
   static xbt::signal<void(Comm const&)> on_recv;
   static xbt::signal<void(Comm const&)> on_start;
 
-  void fire_on_completion() const override { /* Do nothing */ }
+  void fire_on_completion() const override {
+    /* The completion signal of a Comm has to be thrown only once and not by the sender AND the receiver.
+       then Comm::on_completion is thrown in the kernel in CommImpl::finish.
+     */
+  }
   void fire_on_veto() const override { on_veto(const_cast<Comm&>(*this)); }
   void fire_on_suspend() const override { on_suspend(*this); }
   void fire_on_resume() const override { on_resume(*this); }
-- 
2.20.1