mv examples/s4u examples/cpp

[simgrid.git] / examples / cpp / synchro-mutex / s4u-synchro-mutex.cpp

diff --git a/examples/cpp/synchro-mutex/s4u-synchro-mutex.cpp b/examples/cpp/synchro-mutex/s4u-synchro-mutex.cpp
new file mode 100644 (file)
index 0000000..01aa751
--- /dev/null
+++ b/examples/cpp/synchro-mutex/s4u-synchro-mutex.cpp
@@ -0,0 +1,70 @@
+/* Copyright (c) 2006-2021. The SimGrid Team. All rights reserved.          */
+
+/* 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. */
+
+#include <mutex> /* std::mutex and std::lock_guard */
+#include "simgrid/s4u.hpp" /* All of S4U */
+
+constexpr int NB_ACTOR = 6;
+
+XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_test, "a sample log category");
+
+/* This worker uses a classical mutex */
+static void worker(simgrid::s4u::MutexPtr mutex, int& result)
+{
+  // lock the mutex before enter in the critical section
+  mutex->lock();
+
+  XBT_INFO("Hello s4u, I'm ready to compute after a regular lock");
+  // And finally add it to the results
+  result += 1;
+  XBT_INFO("I'm done, good bye");
+
+  // You have to unlock the mutex if you locked it manually.
+  // Beware of exceptions preventing your unlock() from being executed!
+  mutex->unlock();
+}
+
+static void workerLockGuard(simgrid::s4u::MutexPtr mutex, int& result)
+{
+  // Simply use the std::lock_guard like this
+  // It's like a lock() that would do the unlock() automatically when getting out of scope
+  std::lock_guard<simgrid::s4u::Mutex> lock(*mutex);
+
+  // then you are in a safe zone
+  XBT_INFO("Hello s4u, I'm ready to compute after a lock_guard");
+  // update the results
+  result += 1;
+  XBT_INFO("I'm done, good bye");
+
+  // Nothing specific here: the unlock will be automatic
+}
+
+static void master()
+{
+  int result = 0;
+  simgrid::s4u::MutexPtr mutex = simgrid::s4u::Mutex::create();
+
+  for (int i = 0; i < NB_ACTOR * 2 ; i++) {
+    // To create a worker use the static method simgrid::s4u::Actor.
+    if((i % 2) == 0 )
+      simgrid::s4u::Actor::create("worker", simgrid::s4u::Host::by_name("Jupiter"), workerLockGuard, mutex,
+                                  std::ref(result));
+    else
+      simgrid::s4u::Actor::create("worker", simgrid::s4u::Host::by_name("Tremblay"), worker, mutex, std::ref(result));
+  }
+
+  simgrid::s4u::this_actor::sleep_for(10);
+  XBT_INFO("Results is -> %d", result);
+}
+
+int main(int argc, char **argv)
+{
+  simgrid::s4u::Engine e(&argc, argv);
+  e.load_platform("../../platforms/two_hosts.xml");
+  simgrid::s4u::Actor::create("main", simgrid::s4u::Host::by_name("Tremblay"), master);
+  e.run();
+
+  return 0;
+}