This was just approved at the WG21 meeting.
* doc/xml/manual/status_cxx2017.xml: Document P0156R2 status.
* doc/html/*: Regenerate.
* include/std/mutex (scoped_lock): Implement new C++17 template.
* testsuite/30_threads/scoped_lock/cons/1.cc: New test.
* testsuite/30_threads/scoped_lock/requirements/
explicit_instantiation.cc: New test.
* testsuite/30_threads/scoped_lock/requirements/typedefs.cc: New test.
Tested powerpc64le-linux, committed to trunk.
commit 109ebf33d95668712c93627d523afe65354c51f9
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Sun Mar 5 17:39:00 2017 +0000
Add std::scoped_lock for C++17
* doc/xml/manual/status_cxx2017.xml: Document P0156R2 status.
* doc/html/*: Regenerate.
* include/std/mutex (scoped_lock): Implement new C++17 template.
* testsuite/30_threads/scoped_lock/cons/1.cc: New test.
* testsuite/30_threads/scoped_lock/requirements/
explicit_instantiation.cc: New test.
* testsuite/30_threads/scoped_lock/requirements/typedefs.cc: New test.
diff --git a/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
b/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
index add0514..1053f2d 100644
--- a/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
+++ b/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
@@ -719,15 +719,14 @@ Feature-testing recommendations for C++</link>.
</row>
<row>
- <?dbhtml bgcolor="#C8B0B0" ?>
<entry> Variadic <code>lock_guard</code> </entry>
<entry>
- <link xmlns:xlink="http://www.w3.org/1999/xlink";
xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0156r0.html";>
- P0156R0
+ <link xmlns:xlink="http://www.w3.org/1999/xlink";
xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0156r2.html";>
+ P0156R2
</link>
</entry>
- <entry align="center"> No </entry>
- <entry><code> __cpp_lib_lock_guard_variadic >= 201510 </code></entry>
+ <entry align="center"> 7 </entry>
+ <entry><code> __cpp_lib_scoped_lock >= 201703 </code></entry>
</row>
</tbody>
diff --git a/libstdc++-v3/include/std/mutex b/libstdc++-v3/include/std/mutex
index d6f3899..6c3f920 100644
--- a/libstdc++-v3/include/std/mutex
+++ b/libstdc++-v3/include/std/mutex
@@ -556,6 +556,74 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
}
+#if __cplusplus > 201402L
+#define __cpp_lib_scoped_lock 201703
+ /** @brief A scoped lock type for multiple lockable objects.
+ *
+ * A scoped_lock controls mutex ownership within a scope, releasing
+ * ownership in the destructor.
+ */
+ template<typename... _MutexTypes>
+ class scoped_lock
+ {
+ public:
+ explicit scoped_lock(_MutexTypes&... __m) : _M_devices(std::tie(__m...))
+ { std::lock(__m...); }
+
+ explicit scoped_lock(_MutexTypes&... __m, adopt_lock_t) noexcept
+ : _M_devices(std::tie(__m...))
+ { } // calling thread owns mutex
+
+ ~scoped_lock()
+ {
+ std::apply([](_MutexTypes&... __m) {
+ char __i[] __attribute__((__unused__)) = { (__m.unlock(), 0)... };
+ }, _M_devices);
+ }
+
+ scoped_lock(const scoped_lock&) = delete;
+ scoped_lock& operator=(const scoped_lock&) = delete;
+
+ private:
+ tuple<_MutexTypes&...> _M_devices;
+ };
+
+ template<>
+ class scoped_lock<>
+ {
+ public:
+ explicit scoped_lock() = default;
+ explicit scoped_lock(adopt_lock_t) noexcept { }
+ ~scoped_lock() = default;
+
+ scoped_lock(const scoped_lock&) = delete;
+ scoped_lock& operator=(const scoped_lock&) = delete;
+ };
+
+ template<typename _Mutex>
+ class scoped_lock<_Mutex>
+ {
+ public:
+ using mutex_type = _Mutex;
+
+ explicit scoped_lock(mutex_type& __m) : _M_device(__m)
+ { _M_device.lock(); }
+
+ explicit scoped_lock(mutex_type& __m, adopt_lock_t) noexcept
+ : _M_device(__m)
+ { } // calling thread owns mutex
+
+ ~scoped_lock()
+ { _M_device.unlock(); }
+
+ scoped_lock(const scoped_lock&) = delete;
+ scoped_lock& operator=(const scoped_lock&) = delete;
+
+ private:
+ mutex_type& _M_device;
+ };
+#endif // C++17
+
#ifdef _GLIBCXX_HAS_GTHREADS
/// once_flag
struct once_flag
diff --git a/libstdc++-v3/testsuite/30_threads/scoped_lock/cons/1.cc
b/libstdc++-v3/testsuite/30_threads/scoped_lock/cons/1.cc
new file mode 100644
index 0000000..9f1b48c
--- /dev/null
+++ b/libstdc++-v3/testsuite/30_threads/scoped_lock/cons/1.cc
@@ -0,0 +1,133 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do run { target c++1z } }
+// { dg-require-cstdint "" }
+
+// Copyright (C) 2017 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/>.
+
+
+#include <mutex>
+#include <testsuite_hooks.h>
+
+struct BasicLockable
+{
+ BasicLockable() : locked(false) { }
+
+ ~BasicLockable() noexcept(false)
+ {
+ if (locked)
+ throw 0;
+ }
+
+ void lock()
+ {
+ if (locked)
+ throw 0;
+ locked = true;
+ }
+
+ void unlock()
+ {
+ if (!locked)
+ throw 0;
+ locked = false;
+ }
+
+ bool locked;
+};
+
+template<int>
+struct Lockable
+{
+ BasicLockable m;
+ void lock() { m.lock(); }
+ void unlock() { m.unlock(); }
+ bool try_lock() { if (m.locked) return false; m.lock(); return true; }
+};
+
+void test01()
+{
+ BasicLockable m;
+
+ try
+ {
+ std::scoped_lock<BasicLockable> l(m);
+ VERIFY( m.locked );
+ }
+ catch (...)
+ {
+ VERIFY( false );
+ }
+
+ VERIFY( !m.locked );
+
+ m.lock();
+
+ try
+ {
+ std::scoped_lock<BasicLockable> l(m, std::adopt_lock);
+ }
+ catch (...)
+ {
+ VERIFY( false );
+ }
+
+ VERIFY( !m.locked );
+}
+
+void test02()
+{
+ Lockable<1> m1;
+ Lockable<2> m2;
+
+ try
+ {
+ std::scoped_lock<Lockable<1>, Lockable<2>> l(m1, m2);
+ VERIFY( m1.m.locked );
+ VERIFY( m2.m.locked );
+ }
+ catch (...)
+ {
+ VERIFY( false );
+ }
+
+ VERIFY( !m1.m.locked );
+ VERIFY( !m2.m.locked );
+
+ m1.lock();
+ m2.lock();
+
+ try
+ {
+ std::scoped_lock<Lockable<1>, Lockable<2>> l(m1, m2, std::adopt_lock);
+ VERIFY( m1.m.locked );
+ VERIFY( m2.m.locked );
+ }
+ catch (...)
+ {
+ VERIFY( false );
+ }
+
+ VERIFY( !m1.m.locked );
+ VERIFY( !m2.m.locked );
+}
+
+int main()
+{
+ test01();
+ test02();
+}
diff --git
a/libstdc++-v3/testsuite/30_threads/scoped_lock/requirements/explicit_instantiation.cc
b/libstdc++-v3/testsuite/30_threads/scoped_lock/requirements/explicit_instantiation.cc
new file mode 100644
index 0000000..cbf1075
--- /dev/null
+++
b/libstdc++-v3/testsuite/30_threads/scoped_lock/requirements/explicit_instantiation.cc
@@ -0,0 +1,33 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do compile { target c++1z } }
+// { dg-require-cstdint "" }
+// { dg-require-gthreads "" }
+
+// Copyright (C) 2017 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/>.
+
+
+// NB: This file is for testing with NO OTHER INCLUDES.
+
+#include <mutex>
+
+namespace std
+{
+ template class scoped_lock<>;
+ template class scoped_lock<mutex>;
+ template class scoped_lock<recursive_mutex, mutex>;
+}
diff --git
a/libstdc++-v3/testsuite/30_threads/scoped_lock/requirements/typedefs.cc
b/libstdc++-v3/testsuite/30_threads/scoped_lock/requirements/typedefs.cc
new file mode 100644
index 0000000..55756d8
--- /dev/null
+++ b/libstdc++-v3/testsuite/30_threads/scoped_lock/requirements/typedefs.cc
@@ -0,0 +1,33 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do compile { target c++1z } }
+// { dg-require-cstdint "" }
+// { dg-require-gthreads "" }
+
+// Copyright (C) 2017 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/>.
+
+
+// NB: This file is for testing with NO OTHER INCLUDES.
+
+#include <mutex>
+
+void test01()
+{
+ // Check for required typedefs
+ typedef std::scoped_lock<std::mutex> test_type;
+ typedef test_type::mutex_type mutex_type;
+}
