* implemented thread pool

include/ecs/core/mp/core/copy_qualifiers.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <ecs/config.h>
+
+beg_namespace_ecs_core_mp
+{
+
+    template <typename T, typename T_source>
+    using copy_const_qualifier =
+        std::conditional_t<
+            std::is_const<T_source> { },
+            std::add_const_t<T>,
+            T>;
+
+    template <typename T, typename T_source>
+    using copy_volatile_qualifier =
+        std::conditional_t<
+            std::is_volatile<T_source> { },
+            std::add_volatile_t<T>,
+            T>;
+
+    template <typename T, typename T_source>
+    using copy_cv_qualifiers =
+        copy_const_qualifier<
+            copy_volatile_qualifier<T, T_source>,
+            T_source>;
+
+}
+end_namespace_ecs_core_mp

include/ecs/core/system.h

@@ -1,3 +1,5 @@
 #pragma once
 
-#include "./storage/system.h"
+#include "./system/instance.h"
+#include "./system/manager.h"
+#include "./system/storage.h"

include/ecs/core/utils.h

@@ -1,3 +1,7 @@
 #pragma once
 
-#include "./util/scope_guard.h"
+#include "./utils/fixed_function.h"
+#include "./utils/movable_atomic.h"
+#include "./utils/scope_guard.h"
+#include "./utils/storage_cast.h"
+#include "./utils/thread_pool.h"

include/ecs/core/utils/fixed_function.h

@@ -0,0 +1,146 @@
+#pragma once
+
+#include <ecs/config.h>
+
+#include "./storage_cast.h"
+
+beg_namespace_ecs_core_utils
+{
+
+    template<typename T_signature, size_t T_storage_size = 64>
+    struct fixed_function;
+
+    template<typename T_return, typename... T_args, size_t T_storage_size>
+    struct fixed_function<T_return(T_args...), T_storage_size>
+    {
+    private:
+        static constexpr decltype(auto) storage_size = T_storage_size;
+
+        using return_type       = T_return;
+        using storage_type      = std::aligned_storage_t<storage_size, alignof(size_t)>;
+        using function_ptr_type = return_type (*)(T_args...);
+        using method_type       = return_type (*)(storage_type*, function_ptr_type, T_args...);
+        using allocator_type    = void        (*)(storage_type*, void*);
+
+    private:
+        union
+        {
+            storage_type        _storage;
+            function_ptr_type   _function_ptr;
+        };
+        method_type             _method_ptr;
+        allocator_type          _allocator_ptr;
+
+    private:
+        void move_from_other(fixed_function& other) noexcept
+        {
+            assert(this != &o);
+
+            // cleanup
+            if (_allocator_ptr)
+            {
+                _allocator_ptr(&_storage, nullptr);
+            }
+            _allocator_ptr = nullptr;
+            _function_ptr = nullptr;
+
+            // move
+            _method_ptr = other._method_ptr;
+            other._method_ptr = nullptr;
+
+            _function_ptr = other._function_ptr;
+            _allocator_ptr = other._allocator_ptr;
+            if (_allocator_ptr)
+            {
+                _allocator_ptr(&_storage, &other._storage);
+            }
+        }
+
+    public:
+        inline fixed_function() noexcept
+            : _function_ptr (nullptr)
+            , _method_ptr   (nullptr)
+            , _allocator_ptr(nullptr)
+            { }
+
+        template<typename T_func>
+        inline fixed_function(T_func&& func) noexcept
+            : fixed_function()
+        {
+            using unref_type = std::remove_reference_t<T_func>;
+
+            static_assert(
+                sizeof(unref_type) < storage_size,
+                "functional object doesn't fit into internal storage");
+
+            static_assert(
+                std::is_move_constructible<unref_type> { },
+                "should be move constructable");
+
+            _method_ptr = [](storage_type* s, function_ptr_type, T_args... args)
+            {
+                return storage_cast<unref_type>(s)->operator()(args...);
+            };
+
+            _allocator_ptr = [](storage_type* s, void* obj)
+            {
+                if (obj)
+                {
+                    new(s) unref_type(std::move(*static_cast<unref_type*>(obj)));
+                }
+                else
+                {
+                    storage_cast<unref_type>(s)->~unref_type();
+                }
+            };
+
+            _allocator_ptr(&_storage, &func);
+        }
+
+        template<typename TF_return, typename... TF_args>
+        inline fixed_function(TF_return (*func)(TF_args...)) noexcept
+            : fixed_function()
+        {
+            _function_ptr = func;
+            _method_ptr = [](storage_type*, function_ptr_type f, T_args... args)
+            {
+                return static_cast<decltype(func)>(f)(args...);
+            };
+        }
+
+        inline fixed_function(fixed_function&& other) noexcept
+            : fixed_function()
+            { move_from_other(other); }
+
+        fixed_function(const fixed_function&) = delete;
+
+        inline ~fixed_function() noexcept
+        {
+            if (_allocator_ptr)
+            {
+                _allocator_ptr(&_storage, nullptr);
+            }
+            _allocator_ptr = nullptr;
+            _function_ptr = nullptr;
+            _method_ptr = nullptr;
+        }
+        
+        inline fixed_function& operator=(fixed_function&& other) noexcept
+        {
+            move_from_other(other);
+            return *this;
+        }
+
+        fixed_function& operator=(const fixed_function&) = delete;
+
+        template<typename... TF_args>
+        inline decltype(auto) operator()(TF_args&&... args) const
+        {
+            assert(_method_ptr != nullptr);
+            return _method_ptr(&_storage, _function_ptr, std::forward<TF_args>(args)...);
+        }
+
+    };
+
+}
+end_namespace_ecs_core_utils

include/ecs/core/utils/movable_atomic.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <ecs/config.h>
+
+beg_namespace_ecs_core_utils
+{
+
+    template<typename T>
+    struct movable_atomic final
+        : std::atomic<T>
+    {
+    private:
+        using base_type = std::atomic<T>;
+    
+    public:
+        using base_type::base_type;
+
+        movable_atomic() = default;
+
+        movable_atomic(const movable_atomic&) = delete;
+
+        movable_atomic(movable_atomic&& other) noexcept
+            : base_type(other.load())
+            { }
+
+        movable_atomic& operator=(const movable_atomic&) = delete;
+
+        movable_atomic& operator=(movable_atomic&& other) noexcept
+        {
+            this->store(other.load());
+            return *this;
+        }
+
+        template<T value>
+        movable_atomic& operator=(std::integral_constant<T, value> x) noexcept
+        {
+            this->store(decltype(x)::value);
+            return *this;
+        }
+    };
+
+}
+end_namespace_ecs_core_utils

include/ecs/core/utils/storage_cast.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <ecs/config.h>
+
+#include <ecs/core/mp/core/copy_qualifiers.h>
+
+beg_namespace_ecs_core_utils
+{
+
+    template <typename T, typename T_storage>
+    inline constexpr decltype(auto) storage_cast(T_storage* storage) noexcept
+    {
+        static_assert(
+            sizeof(T_storage) >= sizeof(T),
+            "`T_storage` is not big enough for `T`.");
+
+        static_assert(
+            alignof(T_storage) >= alignof(T),
+            "`T_storage` is not properly aligned for `T`.");
+
+        assert(storage != nullptr);
+
+        using return_type = mp::copy_cv_qualifiers<T, T_storage>;
+        return reinterpret_cast<return_type*>(storage);
+    }
+
+
+}
+end_namespace_ecs_core_utils

include/ecs/core/utils/thread_pool.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include "./thread_pool/pool.h"
+#include "./thread_pool/types.h"
+#include "./thread_pool/worker.h"

include/ecs/core/utils/thread_pool/pool.h

@@ -0,0 +1,89 @@
+#pragma once
+
+#include <ecs/config.h>
+
+#include "./worker.h"
+#include "./types.h"
+
+beg_namespace_ecs_core_utils
+{
+
+    struct thread_pool
+    {
+    private:
+        using worker_vector = std::vector<thread_pool_worker>;
+        using atomic_size_t = std::atomic<size_t>;
+
+    private:
+        task_queue      _queue;
+        worker_vector   _workers;
+        atomic_size_t   _outstanding_inits;
+
+        auto all_workers_finished() const noexcept
+        {
+            for (const auto& w : _workers)
+            {
+                if (!w.finished())
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        inline void post_dummy_task()
+            { post([]{ }); }
+
+        void initialize_workers(size_t count)
+        {
+            _workers.reserve(count);
+            for (size_t i = 0; i < count; ++i)
+            {
+                _workers.emplace_back(_queue);
+            }
+
+            _outstanding_inits = count;
+            for (auto& w : _workers)
+            {
+                w.start(_outstanding_inits);
+            }
+        }
+
+    public:
+        inline thread_pool(size_t count)
+            { initialize_workers(count); }
+
+        ~thread_pool()
+        {
+            // wait for uninitialized workers
+            while (_outstanding_inits > 0)
+            {
+                std::this_thread::sleep_for(std::chrono::milliseconds(50));
+            }
+
+            // stop all workers
+            for (auto& w : _workers)
+            {
+                w.stop();
+            }
+
+            // post dummy tasks untill all workers has stopped
+            while (!all_workers_finished())
+            {
+                post_dummy_task();
+            }
+
+            // join the worker threads
+            for (auto& w : _workers)
+            {
+                w.join();
+            }
+        }
+
+        template<typename T_func>
+        inline void post(T_func&& func)
+            { _queue.enqueue(std::forward<T_func>(func)); }
+    };
+
+}
+end_namespace_ecs_core_utils

include/ecs/core/utils/thread_pool/types.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <ecs/config.h>
+#include <moodycamel/blockingconcurrentqueue.h>
+
+#include "../fixed_function.h"
+
+beg_namespace_ecs_core_utils
+{
+
+    using task          = fixed_function<void(), 128>;
+    using task_queue    = moodycamel::BlockingConcurrentQueue<task>;
+
+}
+end_namespace_ecs_core_utils

include/ecs/core/utils/thread_pool/worker.h

@@ -0,0 +1,83 @@
+#pragma once
+
+#include <thread>
+#include <ecs/config.h>
+
+#include "./types.h"
+#include "../movable_atomic.h"
+
+beg_namespace_ecs_core_utils
+{
+
+    struct thread_pool_worker
+    {
+    private:
+        enum class state
+        {
+            uninizialized,
+            running,
+            stopped,
+            finished,
+        };
+
+        using atomic_state = movable_atomic<state>;
+
+        std::thread     _thread;
+        task_queue&     _queue;
+        atomic_state    _state;
+
+    private:
+        void run()
+        {
+            _state = state::running;
+            while (_state == state::running)
+            {
+                task t;
+                if (_queue.wait_dequeue_timed(t, std::chrono::milliseconds(500)))
+                {
+                    t();
+                }
+            }
+            _state = state::finished;
+        }
+
+    public:
+        thread_pool_worker(task_queue& queue) noexcept
+            : _queue(queue)
+            { }
+
+        thread_pool_worker(thread_pool_worker&&) = default;
+        thread_pool_worker(const thread_pool_worker&) = delete;
+
+        thread_pool_worker& operator=(thread_pool_worker&&) = default;
+        thread_pool_worker& operator=(const thread_pool_worker&) = delete;
+
+        template<typename T_counter>
+        inline void start(T_counter& remaining_inits)
+        {
+            _thread = std::thread([this, &remaining_inits]{
+                --remaining_inits;
+                run();
+            });
+        }
+
+        inline void stop() noexcept
+        {
+            assert(_state == state::running);
+            _state = state::stopped;
+        }
+
+        inline void join() noexcept
+        {
+            assert(_thread.joinable());
+            assert(_state == state::finished);
+            _thread.join();
+        }
+
+        inline bool finished() const noexcept
+            { return _state == state::finished; }
+
+    };
+
+}
+end_namespace_ecs_core_utils

include/moodycamel/blockingconcurrentqueue.h

@@ -0,0 +1,981 @@
+// Provides an efficient blocking version of moodycamel::ConcurrentQueue.
+// ©2015-2016 Cameron Desrochers. Distributed under the terms of the simplified
+// BSD license, available at the top of concurrentqueue.h.
+// Uses Jeff Preshing's semaphore implementation (under the terms of its
+// separate zlib license, embedded below).
+
+#pragma once
+
+#include "concurrentqueue.h"
+#include <type_traits>
+#include <cerrno>
+#include <memory>
+#include <chrono>
+#include <ctime>
+
+#if defined(_WIN32)
+// Avoid including windows.h in a header; we only need a handful of
+// items, so we'll redeclare them here (this is relatively safe since
+// the API generally has to remain stable between Windows versions).
+// I know this is an ugly hack but it still beats polluting the global
+// namespace with thousands of generic names or adding a .cpp for nothing.
+extern "C" {
+	struct _SECURITY_ATTRIBUTES;
+	__declspec(dllimport) void* __stdcall CreateSemaphoreW(_SECURITY_ATTRIBUTES* lpSemaphoreAttributes, long lInitialCount, long lMaximumCount, const wchar_t* lpName);
+	__declspec(dllimport) int __stdcall CloseHandle(void* hObject);
+	__declspec(dllimport) unsigned long __stdcall WaitForSingleObject(void* hHandle, unsigned long dwMilliseconds);
+	__declspec(dllimport) int __stdcall ReleaseSemaphore(void* hSemaphore, long lReleaseCount, long* lpPreviousCount);
+}
+#elif defined(__MACH__)
+#include <mach/mach.h>
+#elif defined(__unix__)
+#include <semaphore.h>
+#endif
+
+namespace moodycamel
+{
+namespace details
+{
+	// Code in the mpmc_sema namespace below is an adaptation of Jeff Preshing's
+	// portable + lightweight semaphore implementations, originally from
+	// https://github.com/preshing/cpp11-on-multicore/blob/master/common/sema.h
+	// LICENSE:
+	// Copyright (c) 2015 Jeff Preshing
+	//
+	// This software is provided 'as-is', without any express or implied
+	// warranty. In no event will the authors be held liable for any damages
+	// arising from the use of this software.
+	//
+	// Permission is granted to anyone to use this software for any purpose,
+	// including commercial applications, and to alter it and redistribute it
+	// freely, subject to the following restrictions:
+	//
+	// 1. The origin of this software must not be misrepresented; you must not
+	//	claim that you wrote the original software. If you use this software
+	//	in a product, an acknowledgement in the product documentation would be
+	//	appreciated but is not required.
+	// 2. Altered source versions must be plainly marked as such, and must not be
+	//	misrepresented as being the original software.
+	// 3. This notice may not be removed or altered from any source distribution.
+	namespace mpmc_sema
+	{
+#if defined(_WIN32)
+		class Semaphore
+		{
+		private:
+			void* m_hSema;
+			
+			Semaphore(const Semaphore& other) MOODYCAMEL_DELETE_FUNCTION;
+			Semaphore& operator=(const Semaphore& other) MOODYCAMEL_DELETE_FUNCTION;
+
+		public:
+			Semaphore(int initialCount = 0)
+			{
+				assert(initialCount >= 0);
+				const long maxLong = 0x7fffffff;
+				m_hSema = CreateSemaphoreW(nullptr, initialCount, maxLong, nullptr);
+			}
+
+			~Semaphore()
+			{
+				CloseHandle(m_hSema);
+			}
+
+			void wait()
+			{
+				const unsigned long infinite = 0xffffffff;
+				WaitForSingleObject(m_hSema, infinite);
+			}
+			
+			bool try_wait()
+			{
+				const unsigned long RC_WAIT_TIMEOUT = 0x00000102;
+				return WaitForSingleObject(m_hSema, 0) != RC_WAIT_TIMEOUT;
+			}
+			
+			bool timed_wait(std::uint64_t usecs)
+			{
+				const unsigned long RC_WAIT_TIMEOUT = 0x00000102;
+				return WaitForSingleObject(m_hSema, (unsigned long)(usecs / 1000)) != RC_WAIT_TIMEOUT;
+			}
+
+			void signal(int count = 1)
+			{
+				ReleaseSemaphore(m_hSema, count, nullptr);
+			}
+		};
+#elif defined(__MACH__)
+		//---------------------------------------------------------
+		// Semaphore (Apple iOS and OSX)
+		// Can't use POSIX semaphores due to http://lists.apple.com/archives/darwin-kernel/2009/Apr/msg00010.html
+		//---------------------------------------------------------
+		class Semaphore
+		{
+		private:
+			semaphore_t m_sema;
+
+			Semaphore(const Semaphore& other) MOODYCAMEL_DELETE_FUNCTION;
+			Semaphore& operator=(const Semaphore& other) MOODYCAMEL_DELETE_FUNCTION;
+
+		public:
+			Semaphore(int initialCount = 0)
+			{
+				assert(initialCount >= 0);
+				semaphore_create(mach_task_self(), &m_sema, SYNC_POLICY_FIFO, initialCount);
+			}
+
+			~Semaphore()
+			{
+				semaphore_destroy(mach_task_self(), m_sema);
+			}
+
+			void wait()
+			{
+				semaphore_wait(m_sema);
+			}
+			
+			bool try_wait()
+			{
+				return timed_wait(0);
+			}
+			
+			bool timed_wait(std::uint64_t timeout_usecs)
+			{
+				mach_timespec_t ts;
+				ts.tv_sec = static_cast<unsigned int>(timeout_usecs / 1000000);
+				ts.tv_nsec = (timeout_usecs % 1000000) * 1000;
+
+				// added in OSX 10.10: https://developer.apple.com/library/prerelease/mac/documentation/General/Reference/APIDiffsMacOSX10_10SeedDiff/modules/Darwin.html
+				kern_return_t rc = semaphore_timedwait(m_sema, ts);
+
+				return rc != KERN_OPERATION_TIMED_OUT && rc != KERN_ABORTED;
+			}
+
+			void signal()
+			{
+				semaphore_signal(m_sema);
+			}
+
+			void signal(int count)
+			{
+				while (count-- > 0)
+				{
+					semaphore_signal(m_sema);
+				}
+			}
+		};
+#elif defined(__unix__)
+		//---------------------------------------------------------
+		// Semaphore (POSIX, Linux)
+		//---------------------------------------------------------
+		class Semaphore
+		{
+		private:
+			sem_t m_sema;
+
+			Semaphore(const Semaphore& other) MOODYCAMEL_DELETE_FUNCTION;
+			Semaphore& operator=(const Semaphore& other) MOODYCAMEL_DELETE_FUNCTION;
+
+		public:
+			Semaphore(int initialCount = 0)
+			{
+				assert(initialCount >= 0);
+				sem_init(&m_sema, 0, static_cast<unsigned int>(initialCount));
+			}
+
+			~Semaphore()
+			{
+				sem_destroy(&m_sema);
+			}
+
+			void wait()
+			{
+				// http://stackoverflow.com/questions/2013181/gdb-causes-sem-wait-to-fail-with-eintr-error
+				int rc;
+				do {
+					rc = sem_wait(&m_sema);
+				} while (rc == -1 && errno == EINTR);
+			}
+
+			bool try_wait()
+			{
+				int rc;
+				do {
+					rc = sem_trywait(&m_sema);
+				} while (rc == -1 && errno == EINTR);
+				return !(rc == -1 && errno == EAGAIN);
+			}
+
+			bool timed_wait(std::uint64_t usecs)
+			{
+				struct timespec ts;
+				const int usecs_in_1_sec = 1000000;
+				const int nsecs_in_1_sec = 1000000000;
+				clock_gettime(CLOCK_REALTIME, &ts);
+				ts.tv_sec += usecs / usecs_in_1_sec;
+				ts.tv_nsec += (usecs % usecs_in_1_sec) * 1000;
+				// sem_timedwait bombs if you have more than 1e9 in tv_nsec
+				// so we have to clean things up before passing it in
+				if (ts.tv_nsec >= nsecs_in_1_sec) {
+					ts.tv_nsec -= nsecs_in_1_sec;
+					++ts.tv_sec;
+				}
+
+				int rc;
+				do {
+					rc = sem_timedwait(&m_sema, &ts);
+				} while (rc == -1 && errno == EINTR);
+				return !(rc == -1 && errno == ETIMEDOUT);
+			}
+
+			void signal()
+			{
+				sem_post(&m_sema);
+			}
+
+			void signal(int count)
+			{
+				while (count-- > 0)
+				{
+					sem_post(&m_sema);
+				}
+			}
+		};
+#else
+#error Unsupported platform! (No semaphore wrapper available)
+#endif
+
+		//---------------------------------------------------------
+		// LightweightSemaphore
+		//---------------------------------------------------------
+		class LightweightSemaphore
+		{
+		public:
+			typedef std::make_signed<std::size_t>::type ssize_t;
+
+		private:
+			std::atomic<ssize_t> m_count;
+			Semaphore m_sema;
+
+			bool waitWithPartialSpinning(std::int64_t timeout_usecs = -1)
+			{
+				ssize_t oldCount;
+				// Is there a better way to set the initial spin count?
+				// If we lower it to 1000, testBenaphore becomes 15x slower on my Core i7-5930K Windows PC,
+				// as threads start hitting the kernel semaphore.
+				int spin = 10000;
+				while (--spin >= 0)
+				{
+					oldCount = m_count.load(std::memory_order_relaxed);
+					if ((oldCount > 0) && m_count.compare_exchange_strong(oldCount, oldCount - 1, std::memory_order_acquire, std::memory_order_relaxed))
+						return true;
+					std::atomic_signal_fence(std::memory_order_acquire);	 // Prevent the compiler from collapsing the loop.
+				}
+				oldCount = m_count.fetch_sub(1, std::memory_order_acquire);
+				if (oldCount > 0)
+					return true;
+				if (timeout_usecs < 0)
+				{
+					m_sema.wait();
+					return true;
+				}
+				if (m_sema.timed_wait((std::uint64_t)timeout_usecs))
+					return true;
+				// At this point, we've timed out waiting for the semaphore, but the
+				// count is still decremented indicating we may still be waiting on
+				// it. So we have to re-adjust the count, but only if the semaphore
+				// wasn't signaled enough times for us too since then. If it was, we
+				// need to release the semaphore too.
+				while (true)
+				{
+					oldCount = m_count.load(std::memory_order_acquire);
+					if (oldCount >= 0 && m_sema.try_wait())
+						return true;
+					if (oldCount < 0 && m_count.compare_exchange_strong(oldCount, oldCount + 1, std::memory_order_relaxed, std::memory_order_relaxed))
+						return false;
+				}
+			}
+
+			ssize_t waitManyWithPartialSpinning(ssize_t max, std::int64_t timeout_usecs = -1)
+			{
+				assert(max > 0);
+				ssize_t oldCount;
+				int spin = 10000;
+				while (--spin >= 0)
+				{
+					oldCount = m_count.load(std::memory_order_relaxed);
+					if (oldCount > 0)
+					{
+						ssize_t newCount = oldCount > max ? oldCount - max : 0;
+						if (m_count.compare_exchange_strong(oldCount, newCount, std::memory_order_acquire, std::memory_order_relaxed))
+							return oldCount - newCount;
+					}
+					std::atomic_signal_fence(std::memory_order_acquire);
+				}
+				oldCount = m_count.fetch_sub(1, std::memory_order_acquire);
+				if (oldCount <= 0)
+				{
+					if (timeout_usecs < 0)
+						m_sema.wait();
+					else if (!m_sema.timed_wait((std::uint64_t)timeout_usecs))
+					{
+						while (true)
+						{
+							oldCount = m_count.load(std::memory_order_acquire);
+							if (oldCount >= 0 && m_sema.try_wait())
+								break;
+							if (oldCount < 0 && m_count.compare_exchange_strong(oldCount, oldCount + 1, std::memory_order_relaxed, std::memory_order_relaxed))
+								return 0;
+						}
+					}
+				}
+				if (max > 1)
+					return 1 + tryWaitMany(max - 1);
+				return 1;
+			}
+
+		public:
+			LightweightSemaphore(ssize_t initialCount = 0) : m_count(initialCount)
+			{
+				assert(initialCount >= 0);
+			}
+
+			bool tryWait()
+			{
+				ssize_t oldCount = m_count.load(std::memory_order_relaxed);
+				while (oldCount > 0)
+				{
+					if (m_count.compare_exchange_weak(oldCount, oldCount - 1, std::memory_order_acquire, std::memory_order_relaxed))
+						return true;
+				}
+				return false;
+			}
+
+			void wait()
+			{
+				if (!tryWait())
+					waitWithPartialSpinning();
+			}
+
+			bool wait(std::int64_t timeout_usecs)
+			{
+				return tryWait() || waitWithPartialSpinning(timeout_usecs);
+			}
+
+			// Acquires between 0 and (greedily) max, inclusive
+			ssize_t tryWaitMany(ssize_t max)
+			{
+				assert(max >= 0);
+				ssize_t oldCount = m_count.load(std::memory_order_relaxed);
+				while (oldCount > 0)
+				{
+					ssize_t newCount = oldCount > max ? oldCount - max : 0;
+					if (m_count.compare_exchange_weak(oldCount, newCount, std::memory_order_acquire, std::memory_order_relaxed))
+						return oldCount - newCount;
+				}
+				return 0;
+			}
+
+			// Acquires at least one, and (greedily) at most max
+			ssize_t waitMany(ssize_t max, std::int64_t timeout_usecs)
+			{
+				assert(max >= 0);
+				ssize_t result = tryWaitMany(max);
+				if (result == 0 && max > 0)
+					result = waitManyWithPartialSpinning(max, timeout_usecs);
+				return result;
+			}
+			
+			ssize_t waitMany(ssize_t max)
+			{
+				ssize_t result = waitMany(max, -1);
+				assert(result > 0);
+				return result;
+			}
+
+			void signal(ssize_t count = 1)
+			{
+				assert(count >= 0);
+				ssize_t oldCount = m_count.fetch_add(count, std::memory_order_release);
+				ssize_t toRelease = -oldCount < count ? -oldCount : count;
+				if (toRelease > 0)
+				{
+					m_sema.signal((int)toRelease);
+				}
+			}
+			
+			ssize_t availableApprox() const
+			{
+				ssize_t count = m_count.load(std::memory_order_relaxed);
+				return count > 0 ? count : 0;
+			}
+		};
+	}	// end namespace mpmc_sema
+}	// end namespace details
+
+
+// This is a blocking version of the queue. It has an almost identical interface to
+// the normal non-blocking version, with the addition of various wait_dequeue() methods
+// and the removal of producer-specific dequeue methods.
+template<typename T, typename Traits = ConcurrentQueueDefaultTraits>
+class BlockingConcurrentQueue
+{
+private:
+	typedef ::moodycamel::ConcurrentQueue<T, Traits> ConcurrentQueue;
+	typedef details::mpmc_sema::LightweightSemaphore LightweightSemaphore;
+
+public:
+	typedef typename ConcurrentQueue::producer_token_t producer_token_t;
+	typedef typename ConcurrentQueue::consumer_token_t consumer_token_t;
+	
+	typedef typename ConcurrentQueue::index_t index_t;
+	typedef typename ConcurrentQueue::size_t size_t;
+	typedef typename std::make_signed<size_t>::type ssize_t;
+	
+	static const size_t BLOCK_SIZE = ConcurrentQueue::BLOCK_SIZE;
+	static const size_t EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD = ConcurrentQueue::EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD;
+	static const size_t EXPLICIT_INITIAL_INDEX_SIZE = ConcurrentQueue::EXPLICIT_INITIAL_INDEX_SIZE;
+	static const size_t IMPLICIT_INITIAL_INDEX_SIZE = ConcurrentQueue::IMPLICIT_INITIAL_INDEX_SIZE;
+	static const size_t INITIAL_IMPLICIT_PRODUCER_HASH_SIZE = ConcurrentQueue::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE;
+	static const std::uint32_t EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE = ConcurrentQueue::EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE;
+	static const size_t MAX_SUBQUEUE_SIZE = ConcurrentQueue::MAX_SUBQUEUE_SIZE;
+	
+public:
+	// Creates a queue with at least `capacity` element slots; note that the
+	// actual number of elements that can be inserted without additional memory
+	// allocation depends on the number of producers and the block size (e.g. if
+	// the block size is equal to `capacity`, only a single block will be allocated
+	// up-front, which means only a single producer will be able to enqueue elements
+	// without an extra allocation -- blocks aren't shared between producers).
+	// This method is not thread safe -- it is up to the user to ensure that the
+	// queue is fully constructed before it starts being used by other threads (this
+	// includes making the memory effects of construction visible, possibly with a
+	// memory barrier).
+	explicit BlockingConcurrentQueue(size_t capacity = 6 * BLOCK_SIZE)
+		: inner(capacity), sema(create<LightweightSemaphore>(), &BlockingConcurrentQueue::template destroy<LightweightSemaphore>)
+	{
+		assert(reinterpret_cast<ConcurrentQueue*>((BlockingConcurrentQueue*)1) == &((BlockingConcurrentQueue*)1)->inner && "BlockingConcurrentQueue must have ConcurrentQueue as its first member");
+		if (!sema) {
+			MOODYCAMEL_THROW(std::bad_alloc());
+		}
+	}
+	
+	BlockingConcurrentQueue(size_t minCapacity, size_t maxExplicitProducers, size_t maxImplicitProducers)
+		: inner(minCapacity, maxExplicitProducers, maxImplicitProducers), sema(create<LightweightSemaphore>(), &BlockingConcurrentQueue::template destroy<LightweightSemaphore>)
+	{
+		assert(reinterpret_cast<ConcurrentQueue*>((BlockingConcurrentQueue*)1) == &((BlockingConcurrentQueue*)1)->inner && "BlockingConcurrentQueue must have ConcurrentQueue as its first member");
+		if (!sema) {
+			MOODYCAMEL_THROW(std::bad_alloc());
+		}
+	}
+	
+	// Disable copying and copy assignment
+	BlockingConcurrentQueue(BlockingConcurrentQueue const&) MOODYCAMEL_DELETE_FUNCTION;
+	BlockingConcurrentQueue& operator=(BlockingConcurrentQueue const&) MOODYCAMEL_DELETE_FUNCTION;
+	
+	// Moving is supported, but note that it is *not* a thread-safe operation.
+	// Nobody can use the queue while it's being moved, and the memory effects
+	// of that move must be propagated to other threads before they can use it.
+	// Note: When a queue is moved, its tokens are still valid but can only be
+	// used with the destination queue (i.e. semantically they are moved along
+	// with the queue itself).
+	BlockingConcurrentQueue(BlockingConcurrentQueue&& other) MOODYCAMEL_NOEXCEPT
+		: inner(std::move(other.inner)), sema(std::move(other.sema))
+	{ }
+	
+	inline BlockingConcurrentQueue& operator=(BlockingConcurrentQueue&& other) MOODYCAMEL_NOEXCEPT
+	{
+		return swap_internal(other);
+	}
+	
+	// Swaps this queue's state with the other's. Not thread-safe.
+	// Swapping two queues does not invalidate their tokens, however
+	// the tokens that were created for one queue must be used with
+	// only the swapped queue (i.e. the tokens are tied to the
+	// queue's movable state, not the object itself).
+	inline void swap(BlockingConcurrentQueue& other) MOODYCAMEL_NOEXCEPT
+	{
+		swap_internal(other);
+	}
+	
+private:
+	BlockingConcurrentQueue& swap_internal(BlockingConcurrentQueue& other)
+	{
+		if (this == &other) {
+			return *this;
+		}
+		
+		inner.swap(other.inner);
+		sema.swap(other.sema);
+		return *this;
+	}
+	
+public:
+	// Enqueues a single item (by copying it).
+	// Allocates memory if required. Only fails if memory allocation fails (or implicit
+	// production is disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE is 0,
+	// or Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
+	// Thread-safe.
+	inline bool enqueue(T const& item)
+	{
+		if ((details::likely)(inner.enqueue(item))) {
+			sema->signal();
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues a single item (by moving it, if possible).
+	// Allocates memory if required. Only fails if memory allocation fails (or implicit
+	// production is disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE is 0,
+	// or Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
+	// Thread-safe.
+	inline bool enqueue(T&& item)
+	{
+		if ((details::likely)(inner.enqueue(std::move(item)))) {
+			sema->signal();
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues a single item (by copying it) using an explicit producer token.
+	// Allocates memory if required. Only fails if memory allocation fails (or
+	// Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
+	// Thread-safe.
+	inline bool enqueue(producer_token_t const& token, T const& item)
+	{
+		if ((details::likely)(inner.enqueue(token, item))) {
+			sema->signal();
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues a single item (by moving it, if possible) using an explicit producer token.
+	// Allocates memory if required. Only fails if memory allocation fails (or
+	// Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
+	// Thread-safe.
+	inline bool enqueue(producer_token_t const& token, T&& item)
+	{
+		if ((details::likely)(inner.enqueue(token, std::move(item)))) {
+			sema->signal();
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues several items.
+	// Allocates memory if required. Only fails if memory allocation fails (or
+	// implicit production is disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE
+	// is 0, or Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
+	// Note: Use std::make_move_iterator if the elements should be moved instead of copied.
+	// Thread-safe.
+	template<typename It>
+	inline bool enqueue_bulk(It itemFirst, size_t count)
+	{
+		if ((details::likely)(inner.enqueue_bulk(std::forward<It>(itemFirst), count))) {
+			sema->signal((LightweightSemaphore::ssize_t)(ssize_t)count);
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues several items using an explicit producer token.
+	// Allocates memory if required. Only fails if memory allocation fails
+	// (or Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
+	// Note: Use std::make_move_iterator if the elements should be moved
+	// instead of copied.
+	// Thread-safe.
+	template<typename It>
+	inline bool enqueue_bulk(producer_token_t const& token, It itemFirst, size_t count)
+	{
+		if ((details::likely)(inner.enqueue_bulk(token, std::forward<It>(itemFirst), count))) {
+			sema->signal((LightweightSemaphore::ssize_t)(ssize_t)count);
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues a single item (by copying it).
+	// Does not allocate memory. Fails if not enough room to enqueue (or implicit
+	// production is disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE
+	// is 0).
+	// Thread-safe.
+	inline bool try_enqueue(T const& item)
+	{
+		if (inner.try_enqueue(item)) {
+			sema->signal();
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues a single item (by moving it, if possible).
+	// Does not allocate memory (except for one-time implicit producer).
+	// Fails if not enough room to enqueue (or implicit production is
+	// disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE is 0).
+	// Thread-safe.
+	inline bool try_enqueue(T&& item)
+	{
+		if (inner.try_enqueue(std::move(item))) {
+			sema->signal();
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues a single item (by copying it) using an explicit producer token.
+	// Does not allocate memory. Fails if not enough room to enqueue.
+	// Thread-safe.
+	inline bool try_enqueue(producer_token_t const& token, T const& item)
+	{
+		if (inner.try_enqueue(token, item)) {
+			sema->signal();
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues a single item (by moving it, if possible) using an explicit producer token.
+	// Does not allocate memory. Fails if not enough room to enqueue.
+	// Thread-safe.
+	inline bool try_enqueue(producer_token_t const& token, T&& item)
+	{
+		if (inner.try_enqueue(token, std::move(item))) {
+			sema->signal();
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues several items.
+	// Does not allocate memory (except for one-time implicit producer).
+	// Fails if not enough room to enqueue (or implicit production is
+	// disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE is 0).
+	// Note: Use std::make_move_iterator if the elements should be moved
+	// instead of copied.
+	// Thread-safe.
+	template<typename It>
+	inline bool try_enqueue_bulk(It itemFirst, size_t count)
+	{
+		if (inner.try_enqueue_bulk(std::forward<It>(itemFirst), count)) {
+			sema->signal((LightweightSemaphore::ssize_t)(ssize_t)count);
+			return true;
+		}
+		return false;
+	}
+	
+	// Enqueues several items using an explicit producer token.
+	// Does not allocate memory. Fails if not enough room to enqueue.
+	// Note: Use std::make_move_iterator if the elements should be moved
+	// instead of copied.
+	// Thread-safe.
+	template<typename It>
+	inline bool try_enqueue_bulk(producer_token_t const& token, It itemFirst, size_t count)
+	{
+		if (inner.try_enqueue_bulk(token, std::forward<It>(itemFirst), count)) {
+			sema->signal((LightweightSemaphore::ssize_t)(ssize_t)count);
+			return true;
+		}
+		return false;
+	}
+	
+	
+	// Attempts to dequeue from the queue.
+	// Returns false if all producer streams appeared empty at the time they
+	// were checked (so, the queue is likely but not guaranteed to be empty).
+	// Never allocates. Thread-safe.
+	template<typename U>
+	inline bool try_dequeue(U& item)
+	{
+		if (sema->tryWait()) {
+			while (!inner.try_dequeue(item)) {
+				continue;
+			}
+			return true;
+		}
+		return false;
+	}
+	
+	// Attempts to dequeue from the queue using an explicit consumer token.
+	// Returns false if all producer streams appeared empty at the time they
+	// were checked (so, the queue is likely but not guaranteed to be empty).
+	// Never allocates. Thread-safe.
+	template<typename U>
+	inline bool try_dequeue(consumer_token_t& token, U& item)
+	{
+		if (sema->tryWait()) {
+			while (!inner.try_dequeue(token, item)) {
+				continue;
+			}
+			return true;
+		}
+		return false;
+	}
+	
+	// Attempts to dequeue several elements from the queue.
+	// Returns the number of items actually dequeued.
+	// Returns 0 if all producer streams appeared empty at the time they
+	// were checked (so, the queue is likely but not guaranteed to be empty).
+	// Never allocates. Thread-safe.
+	template<typename It>
+	inline size_t try_dequeue_bulk(It itemFirst, size_t max)
+	{
+		size_t count = 0;
+		max = (size_t)sema->tryWaitMany((LightweightSemaphore::ssize_t)(ssize_t)max);
+		while (count != max) {
+			count += inner.template try_dequeue_bulk<It&>(itemFirst, max - count);
+		}
+		return count;
+	}
+	
+	// Attempts to dequeue several elements from the queue using an explicit consumer token.
+	// Returns the number of items actually dequeued.
+	// Returns 0 if all producer streams appeared empty at the time they
+	// were checked (so, the queue is likely but not guaranteed to be empty).
+	// Never allocates. Thread-safe.
+	template<typename It>
+	inline size_t try_dequeue_bulk(consumer_token_t& token, It itemFirst, size_t max)
+	{
+		size_t count = 0;
+		max = (size_t)sema->tryWaitMany((LightweightSemaphore::ssize_t)(ssize_t)max);
+		while (count != max) {
+			count += inner.template try_dequeue_bulk<It&>(token, itemFirst, max - count);
+		}
+		return count;
+	}
+	
+	
+	
+	// Blocks the current thread until there's something to dequeue, then
+	// dequeues it.
+	// Never allocates. Thread-safe.
+	template<typename U>
+	inline void wait_dequeue(U& item)
+	{
+		sema->wait();
+		while (!inner.try_dequeue(item)) {
+			continue;
+		}
+	}
+
+	// Blocks the current thread until either there's something to dequeue
+	// or the timeout (specified in microseconds) expires. Returns false
+	// without setting `item` if the timeout expires, otherwise assigns
+	// to `item` and returns true.
+	// Using a negative timeout indicates an indefinite timeout,
+	// and is thus functionally equivalent to calling wait_dequeue.
+	// Never allocates. Thread-safe.
+	template<typename U>
+	inline bool wait_dequeue_timed(U& item, std::int64_t timeout_usecs)
+	{
+		if (!sema->wait(timeout_usecs)) {
+			return false;
+		}
+		while (!inner.try_dequeue(item)) {
+			continue;
+		}
+		return true;
+	}
+    
+    // Blocks the current thread until either there's something to dequeue
+	// or the timeout expires. Returns false without setting `item` if the
+    // timeout expires, otherwise assigns to `item` and returns true.
+	// Never allocates. Thread-safe.
+	template<typename U, typename Rep, typename Period>
+	inline bool wait_dequeue_timed(U& item, std::chrono::duration<Rep, Period> const& timeout)
+    {
+        return wait_dequeue_timed(item, std::chrono::duration_cast<std::chrono::microseconds>(timeout).count());
+    }
+	
+	// Blocks the current thread until there's something to dequeue, then
+	// dequeues it using an explicit consumer token.
+	// Never allocates. Thread-safe.
+	template<typename U>
+	inline void wait_dequeue(consumer_token_t& token, U& item)
+	{
+		sema->wait();
+		while (!inner.try_dequeue(token, item)) {
+			continue;
+		}
+	}
+	
+	// Blocks the current thread until either there's something to dequeue
+	// or the timeout (specified in microseconds) expires. Returns false
+	// without setting `item` if the timeout expires, otherwise assigns
+	// to `item` and returns true.
+	// Using a negative timeout indicates an indefinite timeout,
+	// and is thus functionally equivalent to calling wait_dequeue.
+	// Never allocates. Thread-safe.
+	template<typename U>
+	inline bool wait_dequeue_timed(consumer_token_t& token, U& item, std::int64_t timeout_usecs)
+	{
+		if (!sema->wait(timeout_usecs)) {
+			return false;
+		}
+		while (!inner.try_dequeue(token, item)) {
+			continue;
+		}
+		return true;
+	}
+    
+    // Blocks the current thread until either there's something to dequeue
+	// or the timeout expires. Returns false without setting `item` if the
+    // timeout expires, otherwise assigns to `item` and returns true.
+	// Never allocates. Thread-safe.
+	template<typename U, typename Rep, typename Period>
+	inline bool wait_dequeue_timed(consumer_token_t& token, U& item, std::chrono::duration<Rep, Period> const& timeout)
+    {
+        return wait_dequeue_timed(token, item, std::chrono::duration_cast<std::chrono::microseconds>(timeout).count());
+    }
+	
+	// Attempts to dequeue several elements from the queue.
+	// Returns the number of items actually dequeued, which will
+	// always be at least one (this method blocks until the queue
+	// is non-empty) and at most max.
+	// Never allocates. Thread-safe.
+	template<typename It>
+	inline size_t wait_dequeue_bulk(It itemFirst, size_t max)
+	{
+		size_t count = 0;
+		max = (size_t)sema->waitMany((LightweightSemaphore::ssize_t)(ssize_t)max);
+		while (count != max) {
+			count += inner.template try_dequeue_bulk<It&>(itemFirst, max - count);
+		}
+		return count;
+	}
+	
+	// Attempts to dequeue several elements from the queue.
+	// Returns the number of items actually dequeued, which can
+	// be 0 if the timeout expires while waiting for elements,
+	// and at most max.
+	// Using a negative timeout indicates an indefinite timeout,
+	// and is thus functionally equivalent to calling wait_dequeue_bulk.
+	// Never allocates. Thread-safe.
+	template<typename It>
+	inline size_t wait_dequeue_bulk_timed(It itemFirst, size_t max, std::int64_t timeout_usecs)
+	{
+		size_t count = 0;
+		max = (size_t)sema->waitMany((LightweightSemaphore::ssize_t)(ssize_t)max, timeout_usecs);
+		while (count != max) {
+			count += inner.template try_dequeue_bulk<It&>(itemFirst, max - count);
+		}
+		return count;
+	}
+    
+    // Attempts to dequeue several elements from the queue.
+	// Returns the number of items actually dequeued, which can
+	// be 0 if the timeout expires while waiting for elements,
+	// and at most max.
+	// Never allocates. Thread-safe.
+	template<typename It, typename Rep, typename Period>
+	inline size_t wait_dequeue_bulk_timed(It itemFirst, size_t max, std::chrono::duration<Rep, Period> const& timeout)
+    {
+        return wait_dequeue_bulk_timed<It&>(itemFirst, max, std::chrono::duration_cast<std::chrono::microseconds>(timeout).count());
+    }
+	
+	// Attempts to dequeue several elements from the queue using an explicit consumer token.
+	// Returns the number of items actually dequeued, which will
+	// always be at least one (this method blocks until the queue
+	// is non-empty) and at most max.
+	// Never allocates. Thread-safe.
+	template<typename It>
+	inline size_t wait_dequeue_bulk(consumer_token_t& token, It itemFirst, size_t max)
+	{
+		size_t count = 0;
+		max = (size_t)sema->waitMany((LightweightSemaphore::ssize_t)(ssize_t)max);
+		while (count != max) {
+			count += inner.template try_dequeue_bulk<It&>(token, itemFirst, max - count);
+		}
+		return count;
+	}
+	
+	// Attempts to dequeue several elements from the queue using an explicit consumer token.
+	// Returns the number of items actually dequeued, which can
+	// be 0 if the timeout expires while waiting for elements,
+	// and at most max.
+	// Using a negative timeout indicates an indefinite timeout,
+	// and is thus functionally equivalent to calling wait_dequeue_bulk.
+	// Never allocates. Thread-safe.
+	template<typename It>
+	inline size_t wait_dequeue_bulk_timed(consumer_token_t& token, It itemFirst, size_t max, std::int64_t timeout_usecs)
+	{
+		size_t count = 0;
+		max = (size_t)sema->waitMany((LightweightSemaphore::ssize_t)(ssize_t)max, timeout_usecs);
+		while (count != max) {
+			count += inner.template try_dequeue_bulk<It&>(token, itemFirst, max - count);
+		}
+		return count;
+	}
+	
+	// Attempts to dequeue several elements from the queue using an explicit consumer token.
+	// Returns the number of items actually dequeued, which can
+	// be 0 if the timeout expires while waiting for elements,
+	// and at most max.
+	// Never allocates. Thread-safe.
+	template<typename It, typename Rep, typename Period>
+	inline size_t wait_dequeue_bulk_timed(consumer_token_t& token, It itemFirst, size_t max, std::chrono::duration<Rep, Period> const& timeout)
+    {
+        return wait_dequeue_bulk_timed<It&>(token, itemFirst, max, std::chrono::duration_cast<std::chrono::microseconds>(timeout).count());
+    }
+	
+	
+	// Returns an estimate of the total number of elements currently in the queue. This
+	// estimate is only accurate if the queue has completely stabilized before it is called
+	// (i.e. all enqueue and dequeue operations have completed and their memory effects are
+	// visible on the calling thread, and no further operations start while this method is
+	// being called).
+	// Thread-safe.
+	inline size_t size_approx() const
+	{
+		return (size_t)sema->availableApprox();
+	}
+	
+	
+	// Returns true if the underlying atomic variables used by
+	// the queue are lock-free (they should be on most platforms).
+	// Thread-safe.
+	static bool is_lock_free()
+	{
+		return ConcurrentQueue::is_lock_free();
+	}
+	
+
+private:
+	template<typename U>
+	static inline U* create()
+	{
+		auto p = (Traits::malloc)(sizeof(U));
+		return p != nullptr ? new (p) U : nullptr;
+	}
+	
+	template<typename U, typename A1>
+	static inline U* create(A1&& a1)
+	{
+		auto p = (Traits::malloc)(sizeof(U));
+		return p != nullptr ? new (p) U(std::forward<A1>(a1)) : nullptr;
+	}
+	
+	template<typename U>
+	static inline void destroy(U* p)
+	{
+		if (p != nullptr) {
+			p->~U();
+		}
+		(Traits::free)(p);
+	}
+	
+private:
+	ConcurrentQueue inner;
+	std::unique_ptr<LightweightSemaphore, void (*)(LightweightSemaphore*)> sema;
+};
+
+
+template<typename T, typename Traits>
+inline void swap(BlockingConcurrentQueue<T, Traits>& a, BlockingConcurrentQueue<T, Traits>& b) MOODYCAMEL_NOEXCEPT
+{
+	a.swap(b);
+}
+
+}	// end namespace moodycamel

test/dummy.cpp

@@ -1,5 +1,7 @@
 #include <gtest/gtest.h>
+#include <thread>
 #include <ecs.h>
+#include <ecs/core.h>
 
 #define MAKE_COMPONENT_TAG(x)                                                       \
     namespace tag                                                                   \
@@ -113,5 +115,4 @@ TEST(DummyTest, fuu)
     context->_storage.for_each([](auto& instance){
         std::cout << type_helper<decltype(instance.system())>::name() << std::endl;
     });
-    EXPECT_TRUE ( true );
 }