This patch implements http://lwg.github.com/issues/lwg-active.html#2067 which has Ready status, as well as fixing two new issues I've reported in the past few hours. The first is that packaged_task's template constructors should be restricted to prevent them from being chosen to copy a packaged_task object and the second is that promise and packaged_task should properly support uses-allocator construction so that if "promise(args...)" is well-formed then so is "promise(allocator_arg, alloc, args...)"
* include/std/future (promise): Add constructors for uses-allocator construction from rvalue promise. (packaged_task): Implement LWG 2067. Add additional constructors for uses-allocator construction. * testsuite/30_threads/packaged_task/cons/3.cc: New. * testsuite/30_threads/packaged_task/cons/alloc2.cc: New. * testsuite/30_threads/promise/cons/alloc2.cc: New. Tested x86_64-linux, committed to trunk.
Index: include/std/future =================================================================== --- include/std/future (revision 180749) +++ include/std/future (working copy) @@ -955,6 +955,12 @@ _M_storage(__future_base::_S_allocate_result<_Res>(__a)) { } + template<typename _Allocator> + promise(allocator_arg_t, const _Allocator&, promise&& __rhs) + : _M_future(std::move(__rhs._M_future)), + _M_storage(std::move(__rhs._M_storage)) + { } + promise(const promise&) = delete; ~promise() @@ -1047,6 +1053,12 @@ _M_storage(__future_base::_S_allocate_result<_Res&>(__a)) { } + template<typename _Allocator> + promise(allocator_arg_t, const _Allocator&, promise&& __rhs) + : _M_future(std::move(__rhs._M_future)), + _M_storage(std::move(__rhs._M_storage)) + { } + promise(const promise&) = delete; ~promise() @@ -1122,6 +1134,12 @@ _M_storage(__future_base::_S_allocate_result<void>(__a)) { } + template<typename _Allocator> + promise(allocator_arg_t, const _Allocator&, promise&& __rhs) + : _M_future(std::move(__rhs._M_future)), + _M_storage(std::move(__rhs._M_storage)) + { } + promise(const promise&) = delete; ~promise() @@ -1270,6 +1288,15 @@ { return std::forward<_Tp>(__t); } }; + template<typename _Task, typename _Fn, bool + = is_same<_Task, typename remove_reference<_Fn>::type>::value> + struct __is_same_pkgdtask + { typedef void __type; }; + + template<typename _Task, typename _Fn> + struct __is_same_pkgdtask<_Task, _Fn, true> + { }; + /// packaged_task template<typename _Res, typename... _ArgTypes> class packaged_task<_Res(_ArgTypes...)> @@ -1281,13 +1308,20 @@ // Construction and destruction packaged_task() noexcept { } - template<typename _Fn> + template<typename _Allocator> explicit + packaged_task(allocator_arg_t, const _Allocator& __a) noexcept + { } + + template<typename _Fn, typename = typename + __is_same_pkgdtask<packaged_task, _Fn>::__type> + explicit packaged_task(_Fn&& __fn) : _M_state(std::make_shared<_State_type>(std::forward<_Fn>(__fn))) { } - template<typename _Fn, typename _Allocator> + template<typename _Fn, typename _Allocator, typename = typename + __is_same_pkgdtask<packaged_task, _Fn>::__type> explicit packaged_task(allocator_arg_t, const _Allocator& __a, _Fn&& __fn) : _M_state(std::allocate_shared<_State_type>(__a, @@ -1301,13 +1335,24 @@ } // No copy - packaged_task(packaged_task&) = delete; - packaged_task& operator=(packaged_task&) = delete; + packaged_task(const packaged_task&) = delete; + packaged_task& operator=(const packaged_task&) = delete; + template<typename _Allocator> + explicit + packaged_task(allocator_arg_t, const _Allocator&, + const packaged_task&) = delete; + // Move support packaged_task(packaged_task&& __other) noexcept { this->swap(__other); } + template<typename _Allocator> + explicit + packaged_task(allocator_arg_t, const _Allocator&, + packaged_task&& __other) noexcept + { this->swap(__other); } + packaged_task& operator=(packaged_task&& __other) noexcept { packaged_task(std::move(__other)).swap(*this); Index: testsuite/30_threads/packaged_task/cons/alloc2.cc =================================================================== --- testsuite/30_threads/packaged_task/cons/alloc2.cc (revision 0) +++ testsuite/30_threads/packaged_task/cons/alloc2.cc (revision 0) @@ -0,0 +1,40 @@ +// { dg-do compile } +// { dg-options "-std=gnu++0x" } +// { dg-require-cstdint "" } +// { dg-require-gthreads "" } +// { dg-require-atomic-builtins "" } + +// Copyright (C) 2011 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +// Test that packaged_task can be default-constructed or move-constructed +// in a context that does uses-allocator construction. + +#include <future> +#include <memory> +#include <tuple> + +using std::packaged_task; +using std::allocator_arg; +using std::allocator; +using std::tuple; + +typedef packaged_task<void()> task; +allocator<task> a; + +tuple<task> t1{ allocator_arg, a }; +tuple<task> t2{ allocator_arg, a, task{} }; Index: testsuite/30_threads/packaged_task/cons/3.cc =================================================================== --- testsuite/30_threads/packaged_task/cons/3.cc (revision 0) +++ testsuite/30_threads/packaged_task/cons/3.cc (revision 0) @@ -0,0 +1,56 @@ +// { dg-do run { target *-*-freebsd* *-*-netbsd* *-*-linux* *-*-solaris* *-*-cygwin *-*-darwin* alpha*-*-osf* mips-sgi-irix6* } } +// { dg-options " -std=gnu++0x -pthread" { target *-*-freebsd* *-*-netbsd* *-*-linux* alpha*-*-osf* mips-sgi-irix6* } } +// { dg-options " -std=gnu++0x -pthreads" { target *-*-solaris* } } +// { dg-options " -std=gnu++0x " { target *-*-cygwin *-*-darwin* } } +// { dg-require-cstdint "" } +// { dg-require-gthreads "" } +// { dg-require-atomic-builtins "" } + +// Copyright (C) 2011 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +// LWG 2067. packaged_task should have deleted copy c'tor with const parameter + +#include <future> +#include <thread> +#include <testsuite_hooks.h> + +template<typename F> +std::future<typename std::result_of<F()>::type> spawn_task(F f) +{ + typedef typename std::result_of<F()>::type result_type; + std::packaged_task<result_type()> task(std::move(f)); + std::future<result_type> res(task.get_future()); + std::thread(std::move(task)).detach(); + return res; +} + +int get_res() +{ + return 42; +} + +void test01() +{ + auto f = spawn_task(get_res); + VERIFY( f.get() == get_res() ); +} + +int main() +{ + test01(); +} Index: testsuite/30_threads/promise/cons/alloc2.cc =================================================================== --- testsuite/30_threads/promise/cons/alloc2.cc (revision 0) +++ testsuite/30_threads/promise/cons/alloc2.cc (revision 0) @@ -0,0 +1,42 @@ +// { dg-do compile } +// { dg-options "-std=gnu++0x" } +// { dg-require-cstdint "" } +// { dg-require-gthreads "" } +// { dg-require-atomic-builtins "" } + +// Copyright (C) 2011 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +// Test that promise can be default-constructed or move-constructed +// in a context that does uses-allocator construction. + +#include <future> +#include <memory> +#include <tuple> + +using std::promise; +using std::allocator_arg; +using std::allocator; +using std::tuple; + +typedef promise<int> p; +typedef promise<int&> pr; +typedef promise<void> pv; +allocator<p> a; + +tuple<p, pr, pv> t1{ allocator_arg, a }; +tuple<p, pr, pv> t2{ allocator_arg, a, p{}, pr{}, pv{} };