This is the right condition that prevents deadlocks! :)

[simgrid.git] / src / gras / Msg / gras_msg_exchange.c

diff --git a/src/gras/Msg/gras_msg_exchange.c b/src/gras/Msg/gras_msg_exchange.c
index 8d40258..ba36513 100644 (file)
--- a/src/gras/Msg/gras_msg_exchange.c
+++ b/src/gras/Msg/gras_msg_exchange.c
@@ -278,7 +278,8 @@ gras_msg_handleall(double period) {
        RETHROW0("Error while waiting for messages: %s");
       xbt_ex_free(e);
     }
-  } while (now - begin < period);
+     /* Epsilon to avoid numerical stability issues were the waited interval is so small that the global clock cannot notice the increment */
+  } while (period - now + begin > 0);
 }
 
 /** @brief Handle an incomming message or timer (or wait up to \a timeOut seconds)
@@ -441,7 +442,7 @@ gras_msg_handle(double timeOut) {
                 "AND IN SIMGRID (process wasn't killed by an assert)",msg.type->name);
     if (!ran_ok)
       THROW1(mismatch_error,0,
-            "Message '%s' refused by all registered callbacks", msg.type->name);
+            "Message '%s' refused by all registered callbacks (maybe your callback misses a 'return 0' at the end)", msg.type->name);
     /* FIXME: gras_datadesc_free not implemented => leaking the payload */
     break;