[/ (C) Copyright 2008-9 Anthony Williams. (C) Copyright 12 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:ScopedThreads Scoped Threads] [heading Synopsis] //#include struct detach; struct join_if_joinable; struct interrupt_and_join_if_joinable; template class strict_scoped_thread; template class scoped_thread; template void swap(scoped_thread& lhs, scoped_threadCallable, Thread>& rhs) noexcept; [section:motivation Motivation] Based on the scoped_thread class defined in C++ Concurrency in Action Boost.Thread defines a thread wrapper class that instead of calling terminate if the thread is joinable on destruction, call a specific action given as template parameter. While the scoped_thread class defined in C++ Concurrency in Action is closer to strict_scoped_thread class that doesn't allows any change in the wrapped thread, Boost.Thread provides a class scoped_thread that provides the same non-deprecated interface as __thread. [endsect] [section:tutorial Tutorial] Scoped Threads are wrappers around a thread that allows the user to state what to do at destruction time. One of the common uses is to join the thread at destruction time so this is the default behavior. This is the single difference respect to a thread. While thread call std::terminate() on the destructor if the thread is joinable, strict_scoped_thread<> or scoped_thread<> join the thread if joinable. The difference between strict_scoped_thread and scoped_thread is that the strict_scoped_thread hides completely the owned thread and so the user can do nothing with the owned thread other than the specific action given as parameter, while scoped_thread provide the same interface as __thread and forwards all the operations. boost::strict_scoped_thread<> t1((boost::thread(f))); //t1.detach(); // compile fails boost::scoped_thread<> t2((boost::thread(f))); t2.detach(); [endsect] [section:thread_functors Free Thread Functors] //#include struct detach; struct join_if_joinable; struct interrupt_and_join_if_joinable; [section:detach Functor `detach`] struct detach { template void operator()(Thread& t) { t.detach(); } }; [endsect] [section:join_if_joinable Functor `join_if_joinable`] struct join_if_joinable { template void operator()(Thread& t) { if (t.joinable()) { t.join(); } } }; [endsect] [section:interrupt_and_join_if_joinable Functor `interrupt_and_join_if_joinable`] struct interrupt_and_join_if_joinable { template void operator()(Thread& t) { t.interrupt(); if (t.joinable()) { t.join(); } } }; [endsect] [endsect] [section:strict_scoped_thread Class `strict_scoped_thread`] // #include template class strict_scoped_thread { thread t_; // for exposition purposes only public: strict_scoped_thread(strict_scoped_thread const&) = delete; strict_scoped_thread& operator=(strict_scoped_thread const&) = delete; explicit strict_scoped_thread(Thread&& t) noexcept; template explicit strict_scoped_thread(F&&, Args&&...); ~strict_scoped_thread(); }; RAII __thread wrapper adding a specific destroyer allowing to master what can be done at destruction time. CallableThread: A callable `void(thread&)`. The default is a `join_if_joinable`. Thread destructor terminates the program if the __thread is joinable. This wrapper can be used to join the thread before destroying it. [heading Example] boost::strict_scoped_thread<> t((boost::thread(F))); [section:default_constructor Constructor from a __thread] explicit strict_scoped_thread(Thread&& t) noexcept; [variablelist [[Effects:] [move the thread to own `t_`]] [[Throws:] [Nothing]] ] [endsect] [section:call_constructor Move Constructor from a Callable] template explicit strict_scoped_thread(F&&, Args&&...); [variablelist [[Effects:] [Construct an internal thread in place.]] [[Postconditions:] [`*this.t_` refers to the newly created thread of execution and `this->get_id()!=thread::id()`.]] [[Throws:] [Any exception the thread construction can throw.]] ] [endsect] [section:destructor Destructor] ~strict_scoped_thread(); [variablelist [[Effects:] [Equivalent to `CallableThread()(t_)`. ]] [[Throws:] [Nothing: The `CallableThread()(t_)` should not throw when joining the thread as the scoped variable is on a scope outside the thread function.]] ] [endsect] [endsect] [section:scoped_thread Class `scoped_thread`] #include template class scoped_thread { thread t_; // for exposition purposes only public: scoped_thread() noexcept; scoped_thread(const scoped_thread&) = delete; scoped_thread& operator=(const scoped_thread&) = delete; explicit scoped_thread(thread&& th) noexcept; template explicit scoped_thread(F&&, Args&&...); ~scoped_thread(); // move support scoped_thread(scoped_thread && x) noexcept; scoped_thread& operator=(scoped_thread && x) noexcept; void swap(scoped_thread& x) noexcept; typedef thread::id id; id get_id() const noexcept; bool joinable() const noexcept; void join(); #ifdef BOOST_THREAD_USES_CHRONO template bool try_join_for(const chrono::duration& rel_time); template bool try_join_until(const chrono::time_point& t); #endif void detach(); static unsigned hardware_concurrency() noexcept; static unsigned physical_concurrency() noexcept; typedef thread::native_handle_type native_handle_type; native_handle_type native_handle(); #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS void interrupt(); bool interruption_requested() const noexcept; #endif }; template void swap(scoped_thread& lhs,scoped_thread& rhs) noexcept; RAII __thread wrapper adding a specific destroyer allowing to master what can be done at destruction time. CallableThread: A callable void(thread&). The default is join_if_joinable. Thread destructor terminates the program if the thread is joinable. This wrapper can be used to join the thread before destroying it. Remark: `scoped_thread` is not a __thread as __thread is not designed to be derived from as a polymorphic type. Anyway `scoped_thread` can be used in most of the contexts a __thread could be used as it has the same non-deprecated interface with the exception of the construction. [heading Example] boost::scoped_thread<> t((boost::thread(F))); t.interrupt(); [section:default_constructor Default Constructor] scoped_thread() noexcept; [variablelist [[Effects:] [Constructs a scoped_thread instance that wraps to __not_a_thread__.]] [[Postconditions:] [`this->get_id()==thread::id()`]] [[Throws:] [Nothing]] ] [endsect] [section:move_constructor Move Constructor] scoped_thread(scoped_thread&& other) noexcept; [variablelist [[Effects:] [Transfers ownership of the scoped_thread managed by `other` (if any) to the newly constructed scoped_thread instance.]] [[Postconditions:] [`other.get_id()==thread::id()` and `get_id()` returns the value of `other.get_id()` prior to the construction]] [[Throws:] [Nothing]] ] [endsect] [section:move_assignment Move assignment operator] scoped_thread& operator=(scoped_thread&& other) noexcept; [variablelist [[Effects:] [Transfers ownership of the scoped_thread managed by `other` (if any) to `*this` after having called to `CallableThread()(t_)`. ]] [[Postconditions:] [`other->get_id()==thread::id()` and `get_id()` returns the value of `other.get_id()` prior to the assignment.]] [[Throws:] [Nothing: The `CallableThread()(t_)` should not throw when joining the thread as the scoped variable is on a scope outside the thread function.]] ] [endsect] [section:thread_constructor Move Constructor from a __thread] scoped_thread(thread&& t); [variablelist [[Effects:] [Transfers ownership of the thread managed by `other` (if any) to the newly constructed scoped_thread instance.]] [[Postconditions:] [other.get_id()==thread::id() and get_id() returns the value of other.get_id() prior to the construction.]] [[Throws:] [Nothing]] ] [endsect] [section:call_constructor Move Constructor from a Callable] template explicit scoped_thread(F&&, Args&&...); [variablelist [[Effects:] [Construct an internal thread in place.]] [[Postconditions:] [`*this.t_` refers to the newly created thread of execution and `this->get_id()!=thread::id()`.]] [[Throws:] [Any exception the thread construction can throw.]] ] [endsect] [section:destructor Destructor] ~scoped_thread(); [variablelist [[Effects:] [Equivalent to `CallableThread()(t_)`. ]] [[Throws:] [Nothing: The `CallableThread()(t_)` should not throw when joining the thread as the scoped variable is on a scope outside the thread function.]] ] [endsect] [section:joinable Member function `joinable()`] bool joinable() const noexcept; [variablelist [[Returns:] [Equivalent to return t_.joinable().]] [[Throws:] [Nothing]] ] [endsect] [section:join Member function `join()`] void join(); [variablelist [[Effects:] [Equivalent to t_.join().]] ] [endsect] [section:try_join_for Member function `try_join_for()`] template bool try_join_for(const chrono::duration& rel_time); [variablelist [[Effects:] [Equivalent to return `t_.try_join_for(rel_time)`.]] ] [endsect] [section:try_join_until Member function `try_join_until()`] template bool try_join_until(const chrono::time_point& abs_time); [variablelist [[Effects:] [Equivalent to return `t_.try_join_until(abs_time)`.]] ] [endsect] [section:detach Member function `detach()`] void detach(); [variablelist [[Effects:] [Equivalent to `t_.detach()`.]] ] [endsect] [section:get_id Member function `get_id()`] thread::id get_id() const noexcept; [variablelist [[Effects:] [Equivalent to return `t_.get_id()`.]] ] [endsect] [section:interrupt Member function `interrupt()`] void interrupt(); [variablelist [[Effects:] [Equivalent to `t_.interrupt()`.]] ] [endsect] [section:hardware_concurrency Static member function `hardware_concurrency()`] unsigned hardware_concurrency() noexecpt; [variablelist [[Effects:] [Equivalent to return `thread::hardware_concurrency()`.]] ] [endsect] [section:physical_concurrency Static member function `physical_concurrency()`] unsigned physical_concurrency() noexecpt; [variablelist [[Effects:] [Equivalent to return `thread::physical_concurrency()`.]] ] [endsect] [section:nativehandle Member function `native_handle()`] typedef thread::native_handle_type native_handle_type; native_handle_type native_handle(); [variablelist [[Effects:] [Equivalent to return `t_.native_handle()`.]] ] [endsect] [section:swap Member function `swap()`] void swap(scoped_thread& other) noexcept; [variablelist [[Effects:] [Equivalent `t_.swap(other.t_)`.]] ] [endsect] [endsect] [section:non_member_swap Non-member function `swap(scoped_thread&,scoped_thread&)`] #include template void swap(scoped_thread& lhs, scoped_threadCallable, Thread>& rhs) noexcept; [variablelist [[Effects:] [`lhs.swap(rhs)`.]] ] [endsect] [endsect]