[futures.task] and [futures.async]. Requires variadics and rvalue-ref support.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@112500 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Howard Hinnant
2010-08-30 18:46:21 +00:00
parent 7158e5c38b
commit 54da338f59
21 changed files with 1834 additions and 25 deletions

View File

@@ -0,0 +1,177 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// template <class F, class... Args>
// future<typename result_of<F(Args...)>::type>
// async(F&& f, Args&&... args);
// template <class F, class... Args>
// future<typename result_of<F(Args...)>::type>
// async(launch policy, F&& f, Args&&... args);
#include <future>
#include <memory>
#include <cassert>
typedef std::chrono::high_resolution_clock Clock;
typedef std::chrono::milliseconds ms;
int f0()
{
std::this_thread::sleep_for(ms(200));
return 3;
}
int i = 0;
int& f1()
{
std::this_thread::sleep_for(ms(200));
return i;
}
void f2()
{
std::this_thread::sleep_for(ms(200));
}
std::unique_ptr<int> f3(int i)
{
std::this_thread::sleep_for(ms(200));
return std::unique_ptr<int>(new int(i));
}
std::unique_ptr<int> f4(std::unique_ptr<int>&& p)
{
std::this_thread::sleep_for(ms(200));
return std::move(p);
}
int main()
{
{
std::future<int> f = std::async(f0);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(f.get() == 3);
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<int> f = std::async(std::launch::async, f0);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(f.get() == 3);
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<int> f = std::async(std::launch::any, f0);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(f.get() == 3);
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<int> f = std::async(std::launch::sync, f0);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(f.get() == 3);
Clock::time_point t1 = Clock::now();
assert(t1-t0 > ms(100));
}
{
std::future<int&> f = std::async(f1);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(&f.get() == &i);
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<int&> f = std::async(std::launch::async, f1);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(&f.get() == &i);
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<int&> f = std::async(std::launch::any, f1);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(&f.get() == &i);
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<int&> f = std::async(std::launch::sync, f1);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(&f.get() == &i);
Clock::time_point t1 = Clock::now();
assert(t1-t0 > ms(100));
}
{
std::future<void> f = std::async(f2);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
f.get();
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<void> f = std::async(std::launch::async, f2);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
f.get();
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<void> f = std::async(std::launch::any, f2);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
f.get();
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<void> f = std::async(std::launch::sync, f2);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
f.get();
Clock::time_point t1 = Clock::now();
assert(t1-t0 > ms(100));
}
{
std::future<std::unique_ptr<int>> f = std::async(f3, 3);
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(*f.get() == 3);
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
{
std::future<std::unique_ptr<int>> f =
std::async(f4, std::unique_ptr<int>(new int(3)));
std::this_thread::sleep_for(ms(300));
Clock::time_point t0 = Clock::now();
assert(*f.get() == 3);
Clock::time_point t1 = Clock::now();
assert(t1-t0 < ms(100));
}
}

View File

@@ -0,0 +1,53 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class promise<R>
// future<R> get_future();
#include <future>
#include <cassert>
int main()
{
{
std::promise<double> p;
std::future<double> f = p.get_future();
p.set_value(105.5);
assert(f.get() == 105.5);
}
{
std::promise<double> p;
std::future<double> f = p.get_future();
try
{
f = p.get_future();
assert(false);
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::future_already_retrieved));
}
}
{
std::promise<double> p;
std::promise<double> p0 = std::move(p);
try
{
std::future<double> f = p.get_future();
assert(false);
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::no_state));
}
}
}

View File

@@ -24,10 +24,10 @@ int main()
std::promise<T> p;
std::future<T> f = p.get_future();
p.set_value(i);
assert(f.get() == 3);
int& j = f.get();
assert(j == 3);
++i;
f = p.get_future();
assert(f.get() == 4);
assert(j == 4);
try
{
p.set_value(i);

View File

@@ -0,0 +1,48 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// packaged_task& operator=(packaged_task&) = delete;
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const {return data_ + i + j;}
};
int main()
{
{
std::packaged_task<double(int, char)> p0(A(5));
std::packaged_task<double(int, char)> p;
p = p0;
assert(!p0);
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p0;
std::packaged_task<double(int, char)> p;
p = p0;
assert(!p0);
assert(!p);
}
}

View File

@@ -0,0 +1,48 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// packaged_task& operator=(packaged_task&& other);
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const {return data_ + i + j;}
};
int main()
{
{
std::packaged_task<double(int, char)> p0(A(5));
std::packaged_task<double(int, char)> p;
p = std::move(p0);
assert(!p0);
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p0;
std::packaged_task<double(int, char)> p;
p = std::move(p0);
assert(!p0);
assert(!p);
}
}

View File

@@ -0,0 +1,46 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// packaged_task(packaged_task&) = delete;
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const {return data_ + i + j;}
};
int main()
{
{
std::packaged_task<double(int, char)> p0(A(5));
std::packaged_task<double(int, char)> p(p0);
assert(!p0);
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p0;
std::packaged_task<double(int, char)> p(p0);
assert(!p0);
assert(!p);
}
}

View File

@@ -0,0 +1,25 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// packaged_task();
#include <future>
#include <cassert>
struct A {};
int main()
{
std::packaged_task<A(int, char)> p;
assert(!p);
}

View File

@@ -0,0 +1,61 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// template <class F>
// explicit packaged_task(F&& f);
#include <future>
#include <cassert>
class A
{
long data_;
public:
static int n_moves;
static int n_copies;
explicit A(long i) : data_(i) {}
A(A&& a) : data_(a.data_) {++n_moves; a.data_ = -1;}
A(const A& a) : data_(a.data_) {++n_copies;}
long operator()(long i, long j) const {return data_ + i + j;}
};
int A::n_moves = 0;
int A::n_copies = 0;
int main()
{
{
std::packaged_task<double(int, char)> p(A(5));
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
assert(A::n_copies == 0);
assert(A::n_moves > 0);
}
A::n_copies == 0;
A::n_copies = 0;
{
A a(5);
std::packaged_task<double(int, char)> p(a);
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
assert(A::n_copies > 0);
assert(A::n_moves > 0);
}
}

View File

@@ -0,0 +1,69 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// template <class F, class Allocator>
// explicit packaged_task(allocator_arg_t, const Allocator& a, F&& f);
#include <future>
#include <cassert>
#include "../../test_allocator.h"
class A
{
long data_;
public:
static int n_moves;
static int n_copies;
explicit A(long i) : data_(i) {}
A(A&& a) : data_(a.data_) {++n_moves; a.data_ = -1;}
A(const A& a) : data_(a.data_) {++n_copies;}
long operator()(long i, long j) const {return data_ + i + j;}
};
int A::n_moves = 0;
int A::n_copies = 0;
int main()
{
{
std::packaged_task<double(int, char)> p(std::allocator_arg,
test_allocator<A>(), A(5));
assert(test_alloc_base::count > 0);
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
assert(A::n_copies == 0);
assert(A::n_moves > 0);
}
assert(test_alloc_base::count == 0);
A::n_copies == 0;
A::n_copies = 0;
{
A a(5);
std::packaged_task<double(int, char)> p(std::allocator_arg,
test_allocator<A>(), a);
assert(test_alloc_base::count > 0);
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
assert(A::n_copies > 0);
assert(A::n_moves > 0);
}
assert(test_alloc_base::count == 0);
}

View File

@@ -0,0 +1,46 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// packaged_task(packaged_task&& other);
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const {return data_ + i + j;}
};
int main()
{
{
std::packaged_task<double(int, char)> p0(A(5));
std::packaged_task<double(int, char)> p = std::move(p0);
assert(!p0);
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p0;
std::packaged_task<double(int, char)> p = std::move(p0);
assert(!p0);
assert(!p);
}
}

View File

@@ -0,0 +1,60 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// ~packaged_task();
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const {return data_ + i + j;}
};
void func(std::packaged_task<double(int, char)>& p)
{
}
void func2(std::packaged_task<double(int, char)>& p)
{
p(3, 'a');
}
int main()
{
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
std::thread(func, std::move(p)).detach();
try
{
double i = f.get();
assert(false);
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::broken_promise));
}
}
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
std::thread(func2, std::move(p)).detach();
assert(f.get() == 105.0);
}
}

View File

@@ -0,0 +1,62 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// future<R> get_future();
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const {return data_ + i + j;}
};
int main()
{
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
try
{
f = p.get_future();
assert(false);
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::future_already_retrieved));
}
}
{
std::packaged_task<double(int, char)> p;
try
{
std::future<double> f = p.get_future();
assert(false);
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::no_state));
}
}
}

View File

@@ -0,0 +1,104 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// void make_ready_at_thread_exit(ArgTypes... args);
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const
{
if (j == 'z')
throw A(6);
return data_ + i + j;
}
};
void func0(std::packaged_task<double(int, char)>& p)
{
std::this_thread::sleep_for(std::chrono::milliseconds(500));
p.make_ready_at_thread_exit(3, 'a');
}
void func1(std::packaged_task<double(int, char)>& p)
{
std::this_thread::sleep_for(std::chrono::milliseconds(500));
p.make_ready_at_thread_exit(3, 'z');
}
void func2(std::packaged_task<double(int, char)>& p)
{
p.make_ready_at_thread_exit(3, 'a');
try
{
p.make_ready_at_thread_exit(3, 'c');
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::promise_already_satisfied));
}
}
void func3(std::packaged_task<double(int, char)>& p)
{
try
{
p.make_ready_at_thread_exit(3, 'a');
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::no_state));
}
}
int main()
{
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
std::thread(func0, std::move(p)).detach();
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
std::thread(func1, std::move(p)).detach();
try
{
f.get();
assert(false);
}
catch (const A& e)
{
assert(e(3, 'a') == 106);
}
}
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
std::thread(func2, std::move(p)).detach();
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p;
std::thread t(func3, std::move(p));
t.join();
}
}

View File

@@ -0,0 +1,105 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// void operator()(ArgTypes... args);
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const
{
if (j == 'z')
throw A(6);
return data_ + i + j;
}
};
void func0(std::packaged_task<double(int, char)>& p)
{
std::this_thread::sleep_for(std::chrono::milliseconds(500));
p(3, 'a');
}
void func1(std::packaged_task<double(int, char)>& p)
{
std::this_thread::sleep_for(std::chrono::milliseconds(500));
p(3, 'z');
}
void func2(std::packaged_task<double(int, char)>& p)
{
p(3, 'a');
try
{
p(3, 'c');
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::promise_already_satisfied));
}
}
void func3(std::packaged_task<double(int, char)>& p)
{
try
{
p(3, 'a');
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::no_state));
}
}
int main()
{
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
std::thread(func0, std::move(p)).detach();
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
std::thread(func1, std::move(p)).detach();
try
{
f.get();
assert(false);
}
catch (const A& e)
{
assert(e(3, 'a') == 106);
}
}
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
std::thread t(func2, std::move(p));
assert(f.get() == 105.0);
t.join();
}
{
std::packaged_task<double(int, char)> p;
std::thread t(func3, std::move(p));
t.join();
}
}

View File

@@ -0,0 +1,58 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// void reset();
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const
{
if (j == 'z')
throw A(6);
return data_ + i + j;
}
};
int main()
{
{
std::packaged_task<double(int, char)> p(A(5));
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
p.reset();
p(4, 'a');
f = p.get_future();
assert(f.get() == 106.0);
}
{
std::packaged_task<double(int, char)> p;
try
{
p.reset();
assert(false);
}
catch (const std::future_error& e)
{
assert(e.code() == make_error_code(std::future_errc::no_state));
}
}
}

View File

@@ -0,0 +1,48 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// void swap(packaged_task& other);
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const {return data_ + i + j;}
};
int main()
{
{
std::packaged_task<double(int, char)> p0(A(5));
std::packaged_task<double(int, char)> p;
p.swap(p0);
assert(!p0);
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p0;
std::packaged_task<double(int, char)> p;
p.swap(p0);
assert(!p0);
assert(!p);
}
}

View File

@@ -0,0 +1,50 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// template <class R, class... ArgTypes>
// void
// swap(packaged_task<R(ArgTypes...)>& x, packaged_task<R(ArgTypes...)>& y);
#include <future>
#include <cassert>
class A
{
long data_;
public:
explicit A(long i) : data_(i) {}
long operator()(long i, long j) const {return data_ + i + j;}
};
int main()
{
{
std::packaged_task<double(int, char)> p0(A(5));
std::packaged_task<double(int, char)> p;
swap(p, p0);
assert(!p0);
assert(p);
std::future<double> f = p.get_future();
p(3, 'a');
assert(f.get() == 105.0);
}
{
std::packaged_task<double(int, char)> p0;
std::packaged_task<double(int, char)> p;
swap(p, p0);
assert(!p0);
assert(!p);
}
}

View File

@@ -0,0 +1,24 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// class packaged_task<R(ArgTypes...)>
// template <class Callable, class Alloc>
// struct uses_allocator<packaged_task<Callable>, Alloc>
// : true_type { };
#include <future>
#include "../../test_allocator.h"
int main()
{
static_assert((std::uses_allocator<std::packaged_task<double(int, char)>, test_allocator<int> >::value), "");
}

View File

@@ -0,0 +1,26 @@
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <future>
// template<class R, class... ArgTypes>
// class packaged_task<R(ArgTypes...)>
// {
// public:
// typedef R result_type;
#include <future>
#include <type_traits>
struct A {};
int main()
{
static_assert((std::is_same<std::packaged_task<A(int, char)>::result_type, A>::value), "");
}