1 /* Copyright (c) 2007-2020. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 /** @addtogroup S4U_examples
8 * - <b>maestro-set/maestro-set.cpp: Switch the system thread hosting our maestro</b>.
9 * That's a very advanced example in which we move the maestro context to another system thread.
10 * Not many users need it (maybe only one, actually), but this example is also a regression test.
12 * This example is in C++ because we use C++11 threads to ensure that the feature is working as
13 * expected. You can still use that feature from a C code.
16 #include "simgrid/Exception.hpp"
17 #include "simgrid/actor.h"
18 #include "simgrid/s4u.hpp"
23 XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_test, "Messages specific for this s4u example");
25 const std::thread::id root_id = std::this_thread::get_id();
27 static void ensure_root_tid()
29 std::thread::id this_id = std::this_thread::get_id();
30 xbt_assert(root_id == this_id, "I was supposed to be the main thread");
31 XBT_INFO("I am the main thread, as expected");
33 static void ensure_other_tid()
35 std::thread::id this_id = std::this_thread::get_id();
36 xbt_assert(this_id != root_id, "I was NOT supposed to be the main thread");
37 XBT_INFO("I am not the main thread, as expected");
43 auto* payload = new std::string("some message");
44 simgrid::s4u::Mailbox::by_name("some mailbox")->put(payload, 10e8);
47 static void receiver()
51 simgrid::s4u::Mailbox::by_name("some mailbox")->get_unique<std::string>();
52 XBT_INFO("Task received");
55 static void maestro(void* /* data */)
58 simgrid::s4u::Actor::create("receiver", simgrid::s4u::Host::by_name("Jupiter"), receiver);
59 simgrid::s4u::Engine::get_instance()->run();
63 int main(int argc, char* argv[])
65 /* Specify which code should be executed by maestro on another thread, once this current thread is affected to an
66 * actor by the subsequent sg_actor_attach(). This must be done before the creation of the engine. */
67 SIMIX_set_maestro(maestro, nullptr);
69 simgrid::s4u::Engine e(&argc, argv);
72 XBT_CRITICAL("Usage: %s platform_file\n", argv[0]);
73 xbt_die("example: %s ../platforms/small_platform.xml\n", argv[0]);
76 e.load_platform(argv[1]);
78 /* Become one of the simulated process (must be done after the platform creation, or the host won't exist). */
79 sg_actor_attach("sender", nullptr, simgrid::s4u::Host::by_name("Tremblay"), nullptr);
81 ensure_root_tid(); // Only useful in this test: we ensure that simgrid is not broken and that this code is executed in
82 // the correct system thread
84 // Execute the sender code. The root thread was actually turned into a regular actor
87 sg_actor_detach(); // The root thread becomes maestro again (as proved by the output)