ceph/src/boost/libs/thread/doc/sync_tutorial.qbk

   1 [/
   2   (C) Copyright 2012 Vicente J. Botet Escriba.
   3   Distributed under the Boost Software License, Version 1.0.
   4   (See accompanying file LICENSE_1_0.txt or copy at
   5   http://www.boost.org/LICENSE_1_0.txt).
   6 ]
   7
   8 [section:tutorial Tutorial]
   9
  10
  11 [@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.
  12
  13
  14 [@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.
  15
  16
  17 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.
  18
  19 [include internal_locking.qbk]
  20
  21 [include external_locking.qbk]
  22
  23 [section:with Executing Around a Function]
  24
  25 In particular, the library provides a way to lock around the execution of a function.
  26
  27   template <class Lockable, class Function, class... Args>
  28   auto with_lock_guard(
  29       Lockable& m,
  30       Function&& func,
  31       Args&&... args
  32   ) -> decltype(func(boost::forward<Args>(args)...)) {
  33     boost::lock_guard<Lockable> lock(m);
  34     return func(boost::forward<Args>(args)...);
  35   }
  36
  37 that can be used with regular functions:
  38
  39   int func(int, int&);
  40   //...
  41   boost::mutex m;
  42   int a;
  43   int result = boost::with_lock_guard(m, func, 1, boost::ref(a));
  44
  45 with boost::bind:
  46
  47   int result = boost::with_lock_guard(
  48       m, boost::bind(func, 2, boost::ref(a))
  49   );
  50
  51 or with lambda expression:
  52
  53   int a;
  54   int result = boost::with_lock_guard(
  55       m,
  56       [&a](int x) {
  57         // this scope is protected by mutex m
  58         a = 3;
  59         return x + 4;
  60       },
  61       5
  62   );
  63
  64 [endsect] [/ With]
  65
  66 [endsect] [/ Tutorial]