bump version to 12.2.2-pve1

[ceph.git] / ceph / src / boost / libs / thread / doc / sync_tutorial.qbk

[/
  (C) Copyright 2012 Vicente J. Botet Escriba.
  Distributed under the Boost Software License, Version 1.0.
  (See accompanying file LICENSE_1_0.txt or copy at
  http://www.boost.org/LICENSE_1_0.txt).
]

[section:tutorial Tutorial]


[@http://web.archive.org/web/20140531071228/http://home.roadrunner.com/~hinnant/mutexes/locking.html Handling mutexes in C++] is an excellent tutorial. You need just replace std and ting by boost.


[@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2406.html Mutex, Lock, Condition Variable Rationale] adds rationale for the design decisions made for mutexes, locks and condition variables.


In addition to the C++11 standard locks, Boost.Thread provides other locks and some utilities that help the user to make their code thread-safe.

[include internal_locking.qbk]

[include external_locking.qbk]

[section:with Executing Around a Function]

In particular, the library provides a way to lock around the execution of a function.

  template <class Lockable, class Function, class... Args>
  auto with_lock_guard(
      Lockable& m,
      Function&& func,
      Args&&... args
  ) -> decltype(func(boost::forward<Args>(args)...)) {
    boost::lock_guard<Lockable> lock(m);
    return func(boost::forward<Args>(args)...);
  }

that can be used with regular functions:

  int func(int, int&);
  //...
  boost::mutex m;
  int a;
  int result = boost::with_lock_guard(m, func, 1, boost::ref(a));

with boost::bind:

  int result = boost::with_lock_guard(
      m, boost::bind(func, 2, boost::ref(a))
  );

or with lambda expression:

  int a;
  int result = boost::with_lock_guard(
      m,
      [&a](int x) {
        // this scope is protected by mutex m
        a = 3;
        return x + 4;
      },
      5
  );

[endsect] [/ With]

[endsect] [/ Tutorial]