Calling front() on empty deque is undefined

- MSG_mailbox_is_empty supposes that it returns nullptr

diff --git a/src/simix/smx_network.cpp b/src/simix/smx_network.cpp
index f2076ab..dcf2c73 100644 (file)
--- a/src/simix/smx_network.cpp
+++ b/src/simix/smx_network.cpp
@@ -70,7 +70,7 @@ smx_mailbox_t SIMIX_mbox_get_by_name(const char *name)
 
 smx_synchro_t SIMIX_mbox_get_head(smx_mailbox_t mbox)
 {
-  return mbox->comm_queue->front();
+  return mbox->comm_queue->empty()? nullptr:mbox->comm_queue->front();
 }
 
 /**