From 6d7383f64b075e36830f416210a1b2e069fdec1c Mon Sep 17 00:00:00 2001
From: Martin Quinson <martin.quinson@loria.fr>
Date: Sun, 10 Sep 2017 18:07:14 +0200
Subject: [PATCH] implement simgrid::s4u::Comm::wait_all() and use it in
 example

---
 examples/s4u/async-waitall/s4u_async-waitall.cpp | 15 ++++++---------
 include/simgrid/s4u/Comm.hpp                     | 15 +++++++++++++--
 2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/examples/s4u/async-waitall/s4u_async-waitall.cpp b/examples/s4u/async-waitall/s4u_async-waitall.cpp
index c7ca1c5e25..f93a699998 100644
--- a/examples/s4u/async-waitall/s4u_async-waitall.cpp
+++ b/examples/s4u/async-waitall/s4u_async-waitall.cpp
@@ -3,14 +3,12 @@
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
-/* This example shows how to use asynchronous communications.
+/* This example shows how to block on the completion of a set of communications.
  *
- * The sender initiate all the messages it wants to send, and then block for their completion.
- * All messages thus occurs concurrently.
+ * As for the other asynchronous examples, the sender initiate all the messages it wants to send and
+ * pack the resulting simgrid::s4u::CommPtr objects in a vector. All messages thus occurs concurrently.
  *
- * On the receiver side, the reception is synchronous.
- *
- * TODO: this example is supposed to test the waitall function, but this is not ported to s4u yet.
+ * The sender then blocks until all ongoing communication terminate, using simgrid::s4u::Comm::wait_all()
  *
  */
 
@@ -66,9 +64,8 @@ void operator()()
   }
   XBT_INFO("Done dispatching all messages");
 
-  /* Now that all message exchanges were initiated, this loop waits for the termination of them all */
-  for (int i = 0; i < messages_count + receivers_count; i++)
-    pending_comms->at(i)->wait();
+  /* Now that all message exchanges were initiated, wait for their completion in one single call */
+  simgrid::s4u::Comm::wait_all(pending_comms);
 
   XBT_INFO("Goodbye now!");
   delete pending_comms;
diff --git a/include/simgrid/s4u/Comm.hpp b/include/simgrid/s4u/Comm.hpp
index c972fe0de5..dcb0e17745 100644
--- a/include/simgrid/s4u/Comm.hpp
+++ b/include/simgrid/s4u/Comm.hpp
@@ -31,8 +31,8 @@ public:
 
   virtual ~Comm();
 
-  /*! take a range of s4u::CommPtr (last excluded) and return when one of them is finished. The return value is an
-   * iterator on the finished Comms. */
+  /*! take a vector s4u::CommPtr and return when one of them is finished.
+   * The return value is the rank of the first finished CommPtr. */
   static int wait_any(std::vector<CommPtr> * comms) { return wait_any_for(comms, -1); }
   /*! Same as wait_any, but with a timeout. If the timeout occurs, parameter last is returned.*/
   static int wait_any_for(std::vector<CommPtr> * comms_in, double timeout)
@@ -54,6 +54,17 @@ public:
     xbt_dynar_free(&comms);
     return idx;
   }
+
+  /*! take a vector s4u::CommPtr and return when all of them is finished. */
+  static void wait_all(std::vector<CommPtr> * comms)
+  {
+    // TODO: this should be a simcall or something
+    // TODO: we are missing a version with timeout
+    for (CommPtr comm : *comms) {
+      comm->wait();
+    }
+  }
+
   /** Creates (but don't start) an async send to the mailbox @p dest */
   static CommPtr XBT_ATTRIB_DEPRECATED_v320("Use Mailbox::put_init(): v3.20 will turn this warning into an error.")
       send_init(MailboxPtr dest)
-- 
2.20.1