[/ (C) Copyright 2007-8 Anthony Williams. 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:changes Changes since boost 1.35] The 1.36.0 release of Boost includes a few new features in the thread library: * New generic __lock_multiple_ref__ and __try_lock_multiple_ref__ functions for locking multiple mutexes at once. * Rvalue reference support for move semantics where the compilers supports it. * A few bugs fixed and missing functions added (including the serious win32 condition variable bug). * `scoped_try_lock` types are now backwards-compatible with Boost 1.34.0 and previous releases. * Support for passing function arguments to the thread function by supplying additional arguments to the __thread__ constructor. * Backwards-compatibility overloads added for `timed_lock` and `timed_wait` functions to allow use of `xtime` for timeouts. [heading Changes since boost 1.34] Almost every line of code in __boost_thread__ has been changed since the 1.34 release of boost. However, most of the interface changes have been extensions, so the new code is largely backwards-compatible with the old code. The new features and breaking changes are described below. [heading New Features] * Instances of __thread__ and of the various lock types are now movable. * Threads can be interrupted at __interruption_points__. * Condition variables can now be used with any type that implements the __lockable_concept__, through the use of `boost::condition_variable_any` (`boost::condition` is a `typedef` to `boost::condition_variable_any`, provided for backwards compatibility). `boost::condition_variable` is provided as an optimization, and will only work with `boost::unique_lock` (`boost::mutex::scoped_lock`). * Thread IDs are separated from __thread__, so a thread can obtain it's own ID (using `boost::this_thread::get_id()`), and IDs can be used as keys in associative containers, as they have the full set of comparison operators. * Timeouts are now implemented using the Boost DateTime library, through a typedef `boost::system_time` for absolute timeouts, and with support for relative timeouts in many cases. `boost::xtime` is supported for backwards compatibility only. * Locks are implemented as publicly accessible templates `boost::lock_guard`, `boost::unique_lock`, `boost::shared_lock`, and `boost::upgrade_lock`, which are templated on the type of the mutex. The __lockable_concept__ has been extended to include publicly available __lock_ref__ and __unlock_ref__ member functions, which are used by the lock types. [heading Breaking Changes] The list below should cover all changes to the public interface which break backwards compatibility. * __try_mutex__ has been removed, and the functionality subsumed into __mutex__. __try_mutex__ is left as a `typedef`, but is no longer a separate class. * __recursive_try_mutex__ has been removed, and the functionality subsumed into __recursive_mutex__. __recursive_try_mutex__ is left as a `typedef`, but is no longer a separate class. * `boost::detail::thread::lock_ops` has been removed. Code that relies on the `lock_ops` implementation detail will no longer work, as this has been removed, as it is no longer necessary now that mutex types now have public __lock_ref__ and __unlock_ref__ member functions. * `scoped_lock` constructors with a second parameter of type `bool` are no longer provided. With previous boost releases, ``boost::mutex::scoped_lock some_lock(some_mutex,false);`` could be used to create a lock object that was associated with a mutex, but did not lock it on construction. This facility has now been replaced with the constructor that takes a `boost::defer_lock_type` as the second parameter: ``boost::mutex::scoped_lock some_lock(some_mutex,boost::defer_lock);`` * The `locked()` member function of the `scoped_lock` types has been renamed to __owns_lock_ref__. * You can no longer obtain a __thread__ instance representing the current thread: a default-constructed __thread__ object is not associated with any thread. The only use for such a thread object was to support the comparison operators: this functionality has been moved to __thread_id__. * The broken `boost::read_write_mutex` has been replaced with __shared_mutex__. * __mutex__ is now never recursive. For Boost releases prior to 1.35 __mutex__ was recursive on Windows and not on POSIX platforms. * When using a __recursive_mutex__ with a call to [cond_any_wait_link `boost::condition_variable_any::wait()`], the mutex is only unlocked one level, and not completely. This prior behaviour was not guaranteed and did not feature in the tests. [endsect]