threads in MinGW

mingw.invoke.h

@@ -0,0 +1,109 @@
+/// \file mingw.invoke.h
+/// \brief Lightweight `invoke` implementation, for C++11 and C++14.
+///
+/// (c) 2018-2019 by Nathaniel J. McClatchey, San Jose, CA, United States
+/// \author Nathaniel J. McClatchey, PhD
+///
+/// \copyright Simplified (2-clause) BSD License.
+///
+/// \note This file may become part of the mingw-w64 runtime package. If/when
+/// this happens, the appropriate license will be added, i.e. this code will
+/// become dual-licensed, and the current BSD 2-clause license will stay.
+
+#ifndef MINGW_INVOKE_H_
+#define MINGW_INVOKE_H_
+
+#include <type_traits>  //  For std::result_of, etc.
+#include <utility>      //  For std::forward
+#include <functional>   //  For std::reference_wrapper
+
+namespace mingw_stdthread
+{
+namespace detail
+{
+//  For compatibility, implement std::invoke for C++11 and C++14
+#if __cplusplus < 201703L
+  template<bool PMemFunc, bool PMemData>
+  struct Invoker
+  {
+    template<class F, class... Args>
+    inline static typename std::result_of<F(Args...)>::type invoke (F&& f, Args&&... args)
+    {
+      return std::forward<F>(f)(std::forward<Args>(args)...);
+    }
+  };
+  template<bool>
+  struct InvokerHelper;
+
+  template<>
+  struct InvokerHelper<false>
+  {
+    template<class T1>
+    inline static auto get (T1&& t1) -> decltype(*std::forward<T1>(t1))
+    {
+      return *std::forward<T1>(t1);
+    }
+
+    template<class T1>
+    inline static auto get (const std::reference_wrapper<T1>& t1) -> decltype(t1.get())
+    {
+      return t1.get();
+    }
+  };
+
+  template<>
+  struct InvokerHelper<true>
+  {
+    template<class T1>
+    inline static auto get (T1&& t1) -> decltype(std::forward<T1>(t1))
+    {
+      return std::forward<T1>(t1);
+    }
+  };
+
+  template<>
+  struct Invoker<true, false>
+  {
+    template<class T, class F, class T1, class... Args>
+    inline static auto invoke (F T::* f, T1&& t1, Args&&... args) ->\
+      decltype((InvokerHelper<std::is_base_of<T,typename std::decay<T1>::type>::value>::get(std::forward<T1>(t1)).*f)(std::forward<Args>(args)...))
+    {
+      return (InvokerHelper<std::is_base_of<T,typename std::decay<T1>::type>::value>::get(std::forward<T1>(t1)).*f)(std::forward<Args>(args)...);
+    }
+  };
+
+  template<>
+  struct Invoker<false, true>
+  {
+    template<class T, class F, class T1, class... Args>
+    inline static auto invoke (F T::* f, T1&& t1, Args&&... args) ->\
+      decltype(InvokerHelper<std::is_base_of<T,typename std::decay<T1>::type>::value>::get(t1).*f)
+    {
+      return InvokerHelper<std::is_base_of<T,typename std::decay<T1>::type>::value>::get(t1).*f;
+    }
+  };
+
+  template<class F, class... Args>
+  struct InvokeResult
+  {
+    typedef Invoker<std::is_member_function_pointer<typename std::remove_reference<F>::type>::value,
+                    std::is_member_object_pointer<typename std::remove_reference<F>::type>::value &&
+                    (sizeof...(Args) == 1)> invoker;
+    inline static auto invoke (F&& f, Args&&... args) -> decltype(invoker::invoke(std::forward<F>(f), std::forward<Args>(args)...))
+    {
+      return invoker::invoke(std::forward<F>(f), std::forward<Args>(args)...);
+    }
+  };
+
+  template<class F, class...Args>
+  auto invoke (F&& f, Args&&... args) -> decltype(InvokeResult<F, Args...>::invoke(std::forward<F>(f), std::forward<Args>(args)...))
+  {
+    return InvokeResult<F, Args...>::invoke(std::forward<F>(f), std::forward<Args>(args)...);
+  }
+#else
+    using std::invoke;
+#endif
+} //  Namespace "detail"
+} //  Namespace "mingw_stdthread"
+
+#endif

mingw.mutex.h

@@ -0,0 +1,491 @@
+/**
+* @file mingw.mutex.h
+* @brief std::mutex et al implementation for MinGW
+** (c) 2013-2016 by Mega Limited, Auckland, New Zealand
+* @author Alexander Vassilev
+*
+* @copyright Simplified (2-clause) BSD License.
+* You should have received a copy of the license along with this
+* program.
+*
+* This code 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.
+* @note
+* This file may become part of the mingw-w64 runtime package. If/when this happens,
+* the appropriate license will be added, i.e. this code will become dual-licensed,
+* and the current BSD 2-clause license will stay.
+*/
+
+#ifndef WIN32STDMUTEX_H
+#define WIN32STDMUTEX_H
+
+#if !defined(__cplusplus) || (__cplusplus < 201103L)
+#error A C++11 compiler is required!
+#endif
+// Recursion checks on non-recursive locks have some performance penalty, and
+// the C++ standard does not mandate them. The user might want to explicitly
+// enable or disable such checks. If the user has no preference, enable such
+// checks in debug builds, but not in release builds.
+#ifdef STDMUTEX_RECURSION_CHECKS
+#elif defined(NDEBUG)
+#define STDMUTEX_RECURSION_CHECKS 0
+#else
+#define STDMUTEX_RECURSION_CHECKS 1
+#endif
+
+#include <chrono>
+#include <system_error>
+#include <atomic>
+#include <mutex> //need for call_once()
+
+#if STDMUTEX_RECURSION_CHECKS || !defined(NDEBUG)
+#include <cstdio>
+#endif
+
+#include <sdkddkver.h>  //  Detect Windows version.
+
+#if (defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR))
+#pragma message "The Windows API that MinGW-w32 provides is not fully compatible\
+ with Microsoft's API. We'll try to work around this, but we can make no\
+ guarantees. This problem does not exist in MinGW-w64."
+#include <windows.h>    //  No further granularity can be expected.
+#else
+#if STDMUTEX_RECURSION_CHECKS
+#include <processthreadsapi.h>  //  For GetCurrentThreadId
+#endif
+#include <synchapi.h> //  For InitializeCriticalSection, etc.
+#include <errhandlingapi.h> //  For GetLastError
+#include <handleapi.h>
+#endif
+
+//  Need for the implementation of invoke
+#include "mingw.invoke.h"
+
+#if !defined(_WIN32_WINNT) || (_WIN32_WINNT < 0x0501)
+#error To use the MinGW-std-threads library, you will need to define the macro _WIN32_WINNT to be 0x0501 (Windows XP) or higher.
+#endif
+
+namespace mingw_stdthread
+{
+//    The _NonRecursive class has mechanisms that do not play nice with direct
+//  manipulation of the native handle. This forward declaration is part of
+//  a friend class declaration.
+#if STDMUTEX_RECURSION_CHECKS
+namespace vista
+{
+class condition_variable;
+}
+#endif
+//    To make this namespace equivalent to the thread-related subset of std,
+//  pull in the classes and class templates supplied by std but not by this
+//  implementation.
+using std::lock_guard;
+using std::unique_lock;
+using std::adopt_lock_t;
+using std::defer_lock_t;
+using std::try_to_lock_t;
+using std::adopt_lock;
+using std::defer_lock;
+using std::try_to_lock;
+
+class recursive_mutex
+{
+    CRITICAL_SECTION mHandle;
+public:
+    typedef LPCRITICAL_SECTION native_handle_type;
+    native_handle_type native_handle() {return &mHandle;}
+    recursive_mutex() noexcept : mHandle()
+    {
+        InitializeCriticalSection(&mHandle);
+    }
+    recursive_mutex (const recursive_mutex&) = delete;
+    recursive_mutex& operator=(const recursive_mutex&) = delete;
+    ~recursive_mutex() noexcept
+    {
+        DeleteCriticalSection(&mHandle);
+    }
+    void lock()
+    {
+        EnterCriticalSection(&mHandle);
+    }
+    void unlock()
+    {
+        LeaveCriticalSection(&mHandle);
+    }
+    bool try_lock()
+    {
+        return (TryEnterCriticalSection(&mHandle)!=0);
+    }
+};
+
+#if STDMUTEX_RECURSION_CHECKS
+struct _OwnerThread
+{
+//    If this is to be read before locking, then the owner-thread variable must
+//  be atomic to prevent a torn read from spuriously causing errors.
+    std::atomic<DWORD> mOwnerThread;
+    constexpr _OwnerThread () noexcept : mOwnerThread(0) {}
+    static void on_deadlock (void)
+    {
+        using namespace std;
+        fprintf(stderr, "FATAL: Recursive locking of non-recursive mutex\
+ detected. Throwing system exception\n");
+        fflush(stderr);
+        throw system_error(make_error_code(errc::resource_deadlock_would_occur));
+    }
+    DWORD checkOwnerBeforeLock() const
+    {
+        DWORD self = GetCurrentThreadId();
+        if (mOwnerThread.load(std::memory_order_relaxed) == self)
+            on_deadlock();
+        return self;
+    }
+    void setOwnerAfterLock(DWORD id)
+    {
+        mOwnerThread.store(id, std::memory_order_relaxed);
+    }
+    void checkSetOwnerBeforeUnlock()
+    {
+        DWORD self = GetCurrentThreadId();
+        if (mOwnerThread.load(std::memory_order_relaxed) != self)
+            on_deadlock();
+        mOwnerThread.store(0, std::memory_order_relaxed);
+    }
+};
+#endif
+
+//    Though the Slim Reader-Writer (SRW) locks used here are not complete until
+//  Windows 7, implementing partial functionality in Vista will simplify the
+//  interaction with condition variables.
+#if defined(_WIN32) && (WINVER >= _WIN32_WINNT_VISTA)
+namespace windows7
+{
+class mutex
+{
+    SRWLOCK mHandle;
+//  Track locking thread for error checking.
+#if STDMUTEX_RECURSION_CHECKS
+    friend class vista::condition_variable;
+    _OwnerThread mOwnerThread {};
+#endif
+public:
+    typedef PSRWLOCK native_handle_type;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wzero-as-null-pointer-constant"
+    constexpr mutex () noexcept : mHandle(SRWLOCK_INIT) { }
+#pragma GCC diagnostic pop
+    mutex (const mutex&) = delete;
+    mutex & operator= (const mutex&) = delete;
+    void lock (void)
+    {
+//  Note: Undefined behavior if called recursively.
+#if STDMUTEX_RECURSION_CHECKS
+        DWORD self = mOwnerThread.checkOwnerBeforeLock();
+#endif
+        AcquireSRWLockExclusive(&mHandle);
+#if STDMUTEX_RECURSION_CHECKS
+        mOwnerThread.setOwnerAfterLock(self);
+#endif
+    }
+    void unlock (void)
+    {
+#if STDMUTEX_RECURSION_CHECKS
+        mOwnerThread.checkSetOwnerBeforeUnlock();
+#endif
+        ReleaseSRWLockExclusive(&mHandle);
+    }
+//  TryAcquireSRW functions are a Windows 7 feature.
+#if (WINVER >= _WIN32_WINNT_WIN7)
+    bool try_lock (void)
+    {
+#if STDMUTEX_RECURSION_CHECKS
+        DWORD self = mOwnerThread.checkOwnerBeforeLock();
+#endif
+        BOOL ret = TryAcquireSRWLockExclusive(&mHandle);
+#if STDMUTEX_RECURSION_CHECKS
+        if (ret)
+            mOwnerThread.setOwnerAfterLock(self);
+#endif
+        return ret;
+    }
+#endif
+    native_handle_type native_handle (void)
+    {
+        return &mHandle;
+    }
+};
+} //  Namespace windows7
+#endif  //  Compiling for Vista
+namespace xp
+{
+class mutex
+{
+    CRITICAL_SECTION mHandle;
+    std::atomic_uchar mState;
+//  Track locking thread for error checking.
+#if STDMUTEX_RECURSION_CHECKS
+    friend class vista::condition_variable;
+    _OwnerThread mOwnerThread {};
+#endif
+public:
+    typedef PCRITICAL_SECTION native_handle_type;
+    constexpr mutex () noexcept : mHandle(), mState(2) { }
+    mutex (const mutex&) = delete;
+    mutex & operator= (const mutex&) = delete;
+    ~mutex() noexcept
+    {
+//    Undefined behavior if the mutex is held (locked) by any thread.
+//    Undefined behavior if a thread terminates while holding ownership of the
+//  mutex.
+        DeleteCriticalSection(&mHandle);
+    }
+    void lock (void)
+    {
+        unsigned char state = mState.load(std::memory_order_acquire);
+        while (state) {
+            if ((state == 2) && mState.compare_exchange_weak(state, 1, std::memory_order_acquire))
+            {
+                InitializeCriticalSection(&mHandle);
+                mState.store(0, std::memory_order_release);
+                break;
+            }
+            if (state == 1)
+            {
+                Sleep(0);
+                state = mState.load(std::memory_order_acquire);
+            }
+        }
+#if STDMUTEX_RECURSION_CHECKS
+        DWORD self = mOwnerThread.checkOwnerBeforeLock();
+#endif
+        EnterCriticalSection(&mHandle);
+#if STDMUTEX_RECURSION_CHECKS
+        mOwnerThread.setOwnerAfterLock(self);
+#endif
+    }
+    void unlock (void)
+    {
+#if STDMUTEX_RECURSION_CHECKS
+        mOwnerThread.checkSetOwnerBeforeUnlock();
+#endif
+        LeaveCriticalSection(&mHandle);
+    }
+    bool try_lock (void)
+    {
+        unsigned char state = mState.load(std::memory_order_acquire);
+        if ((state == 2) && mState.compare_exchange_strong(state, 1, std::memory_order_acquire))
+        {
+            InitializeCriticalSection(&mHandle);
+            mState.store(0, std::memory_order_release);
+        }
+        if (state == 1)
+            return false;
+#if STDMUTEX_RECURSION_CHECKS
+        DWORD self = mOwnerThread.checkOwnerBeforeLock();
+#endif
+        BOOL ret = TryEnterCriticalSection(&mHandle);
+#if STDMUTEX_RECURSION_CHECKS
+        if (ret)
+            mOwnerThread.setOwnerAfterLock(self);
+#endif
+        return ret;
+    }
+    native_handle_type native_handle (void)
+    {
+        return &mHandle;
+    }
+};
+} //  Namespace "xp"
+#if (WINVER >= _WIN32_WINNT_WIN7)
+using windows7::mutex;
+#else
+using xp::mutex;
+#endif
+
+class recursive_timed_mutex
+{
+    static constexpr DWORD kWaitAbandoned = 0x00000080l;
+    static constexpr DWORD kWaitObject0 = 0x00000000l;
+    static constexpr DWORD kInfinite = 0xffffffffl;
+    inline bool try_lock_internal (DWORD ms) noexcept
+    {
+        DWORD ret = WaitForSingleObject(mHandle, ms);
+#ifndef NDEBUG
+        if (ret == kWaitAbandoned)
+        {
+            using namespace std;
+            fprintf(stderr, "FATAL: Thread terminated while holding a mutex.");
+            terminate();
+        }
+#endif
+        return (ret == kWaitObject0) || (ret == kWaitAbandoned);
+    }
+protected:
+    HANDLE mHandle;
+//    Track locking thread for error checking of non-recursive timed_mutex. For
+//  standard compliance, this must be defined in same class and at the same
+//  access-control level as every other variable in the timed_mutex.
+#if STDMUTEX_RECURSION_CHECKS
+    friend class vista::condition_variable;
+    _OwnerThread mOwnerThread {};
+#endif
+public:
+    typedef HANDLE native_handle_type;
+    native_handle_type native_handle() const {return mHandle;}
+    recursive_timed_mutex(const recursive_timed_mutex&) = delete;
+    recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
+    recursive_timed_mutex(): mHandle(CreateMutex(NULL, FALSE, NULL)) {}
+    ~recursive_timed_mutex()
+    {
+        CloseHandle(mHandle);
+    }
+    void lock()
+    {
+        DWORD ret = WaitForSingleObject(mHandle, kInfinite);
+//    If (ret == WAIT_ABANDONED), then the thread that held ownership was
+//  terminated. Behavior is undefined, but Windows will pass ownership to this
+//  thread.
+#ifndef NDEBUG
+        if (ret == kWaitAbandoned)
+        {
+            using namespace std;
+            fprintf(stderr, "FATAL: Thread terminated while holding a mutex.");
+            terminate();
+        }
+#endif
+        if ((ret != kWaitObject0) && (ret != kWaitAbandoned))
+        {
+            throw std::system_error(GetLastError(), std::system_category());
+        }
+    }
+    void unlock()
+    {
+        if (!ReleaseMutex(mHandle))
+            throw std::system_error(GetLastError(), std::system_category());
+    }
+    bool try_lock()
+    {
+        return try_lock_internal(0);
+    }
+    template <class Rep, class Period>
+    bool try_lock_for(const std::chrono::duration<Rep,Period>& dur)
+    {
+        using namespace std::chrono;
+        auto timeout = duration_cast<milliseconds>(dur).count();
+        while (timeout > 0)
+        {
+          constexpr auto kMaxStep = static_cast<decltype(timeout)>(kInfinite-1);
+          auto step = (timeout < kMaxStep) ? timeout : kMaxStep;
+          if (try_lock_internal(static_cast<DWORD>(step)))
+            return true;
+          timeout -= step;
+        }
+        return false;
+    }
+    template <class Clock, class Duration>
+    bool try_lock_until(const std::chrono::time_point<Clock,Duration>& timeout_time)
+    {
+        return try_lock_for(timeout_time - Clock::now());
+    }
+};
+
+//  Override if, and only if, it is necessary for error-checking.
+#if STDMUTEX_RECURSION_CHECKS
+class timed_mutex: recursive_timed_mutex
+{
+public:
+    timed_mutex(const timed_mutex&) = delete;
+    timed_mutex& operator=(const timed_mutex&) = delete;
+    void lock()
+    {
+        DWORD self = mOwnerThread.checkOwnerBeforeLock();
+        recursive_timed_mutex::lock();
+        mOwnerThread.setOwnerAfterLock(self);
+    }
+    void unlock()
+    {
+        mOwnerThread.checkSetOwnerBeforeUnlock();
+        recursive_timed_mutex::unlock();
+    }
+    template <class Rep, class Period>
+    bool try_lock_for(const std::chrono::duration<Rep,Period>& dur)
+    {
+        DWORD self = mOwnerThread.checkOwnerBeforeLock();
+        bool ret = recursive_timed_mutex::try_lock_for(dur);
+        if (ret)
+            mOwnerThread.setOwnerAfterLock(self);
+        return ret;
+    }
+    template <class Clock, class Duration>
+    bool try_lock_until(const std::chrono::time_point<Clock,Duration>& timeout_time)
+    {
+        return try_lock_for(timeout_time - Clock::now());
+    }
+    bool try_lock ()
+    {
+        return try_lock_for(std::chrono::milliseconds(0));
+    }
+};
+#else
+typedef recursive_timed_mutex timed_mutex;
+#endif
+
+class once_flag
+{
+//    When available, the SRW-based mutexes should be faster than the
+//  CriticalSection-based mutexes. Only try_lock will be unavailable in Vista,
+//  and try_lock is not used by once_flag.
+#if (_WIN32_WINNT == _WIN32_WINNT_VISTA)
+    windows7::mutex mMutex;
+#else
+    mutex mMutex;
+#endif
+    std::atomic_bool mHasRun;
+    once_flag(const once_flag&) = delete;
+    once_flag& operator=(const once_flag&) = delete;
+    template<class Callable, class... Args>
+    friend void call_once(once_flag& once, Callable&& f, Args&&... args);
+public:
+    constexpr once_flag() noexcept: mMutex(), mHasRun(false) {}
+};
+
+template<class Callable, class... Args>
+void call_once(once_flag& flag, Callable&& func, Args&&... args)
+{
+    if (flag.mHasRun.load(std::memory_order_acquire))
+        return;
+    lock_guard<decltype(flag.mMutex)> lock(flag.mMutex);
+    if (flag.mHasRun.load(std::memory_order_acquire))
+        return;
+    detail::invoke(std::forward<Callable>(func),std::forward<Args>(args)...);
+    flag.mHasRun.store(true, std::memory_order_release);
+}
+} //  Namespace mingw_stdthread
+
+//  Push objects into std, but only if they are not already there.
+namespace std
+{
+//    Because of quirks of the compiler, the common "using namespace std;"
+//  directive would flatten the namespaces and introduce ambiguity where there
+//  was none. Direct specification (std::), however, would be unaffected.
+//    Take the safe option, and include only in the presence of MinGW's win32
+//  implementation.
+#if defined(__MINGW32__ ) && !defined(_GLIBCXX_HAS_GTHREADS)
+using mingw_stdthread::recursive_mutex;
+using mingw_stdthread::mutex;
+using mingw_stdthread::recursive_timed_mutex;
+using mingw_stdthread::timed_mutex;
+using mingw_stdthread::once_flag;
+using mingw_stdthread::call_once;
+#elif !defined(MINGW_STDTHREAD_REDUNDANCY_WARNING)  //  Skip repetition
+#define MINGW_STDTHREAD_REDUNDANCY_WARNING
+#pragma message "This version of MinGW seems to include a win32 port of\
+ pthreads, and probably already has C++11 std threading classes implemented,\
+ based on pthreads. These classes, found in namespace std, are not overridden\
+ by the mingw-std-thread library. If you would still like to use this\
+ implementation (as it is more lightweight), use the classes provided in\
+ namespace mingw_stdthread."
+#endif
+}
+#endif // WIN32STDMUTEX_H

mingw.thread.h

@@ -0,0 +1,360 @@
+/**
+* @file mingw.thread.h
+* @brief std::thread implementation for MinGW
+* (c) 2013-2016 by Mega Limited, Auckland, New Zealand
+* @author Alexander Vassilev
+*
+* @copyright Simplified (2-clause) BSD License.
+* You should have received a copy of the license along with this
+* program.
+*
+* This code 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.
+* @note
+* This file may become part of the mingw-w64 runtime package. If/when this happens,
+* the appropriate license will be added, i.e. this code will become dual-licensed,
+* and the current BSD 2-clause license will stay.
+*/
+
+#ifndef WIN32STDTHREAD_H
+#define WIN32STDTHREAD_H
+
+#if !defined(__cplusplus) || (__cplusplus < 201103L)
+#error A C++11 compiler is required!
+#endif
+
+//  Use the standard classes for std::, if available.
+#include <thread>
+
+#include <cstddef>      //  For std::size_t
+#include <cerrno>       //  Detect error type.
+#include <exception>    //  For std::terminate
+#include <system_error> //  For std::system_error
+#include <functional>   //  For std::hash
+#include <tuple>        //  For std::tuple
+#include <chrono>       //  For sleep timing.
+#include <memory>       //  For std::unique_ptr
+#include <iosfwd>       //  Stream output for thread ids.
+#include <utility>      //  For std::swap, std::forward
+
+#include "mingw.invoke.h"
+
+#if (defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR))
+#pragma message "The Windows API that MinGW-w32 provides is not fully compatible\
+ with Microsoft's API. We'll try to work around this, but we can make no\
+ guarantees. This problem does not exist in MinGW-w64."
+#include <windows.h>    //  No further granularity can be expected.
+#else
+#include <synchapi.h>   //  For WaitForSingleObject
+#include <handleapi.h>  //  For CloseHandle, etc.
+#include <sysinfoapi.h> //  For GetNativeSystemInfo
+#include <processthreadsapi.h>  //  For GetCurrentThreadId
+#endif
+#include <process.h>  //  For _beginthreadex
+
+#ifndef NDEBUG
+#include <cstdio>
+#endif
+
+#if !defined(_WIN32_WINNT) || (_WIN32_WINNT < 0x0501)
+#error To use the MinGW-std-threads library, you will need to define the macro _WIN32_WINNT to be 0x0501 (Windows XP) or higher.
+#endif
+
+//  Instead of INVALID_HANDLE_VALUE, _beginthreadex returns 0.
+namespace mingw_stdthread
+{
+namespace detail
+{
+    template<std::size_t...>
+    struct IntSeq {};
+
+    template<std::size_t N, std::size_t... S>
+    struct GenIntSeq : GenIntSeq<N-1, N-1, S...> { };
+
+    template<std::size_t... S>
+    struct GenIntSeq<0, S...> { typedef IntSeq<S...> type; };
+
+//    Use a template specialization to avoid relying on compiler optimization
+//  when determining the parameter integer sequence.
+    template<class Func, class T, typename... Args>
+    class ThreadFuncCall;
+// We can't define the Call struct in the function - the standard forbids template methods in that case
+    template<class Func, std::size_t... S, typename... Args>
+    class ThreadFuncCall<Func, detail::IntSeq<S...>, Args...>
+    {
+        static_assert(sizeof...(S) == sizeof...(Args), "Args must match.");
+        using Tuple = std::tuple<typename std::decay<Args>::type...>;
+        typename std::decay<Func>::type mFunc;
+        Tuple mArgs;
+
+    public:
+        ThreadFuncCall(Func&& aFunc, Args&&... aArgs)
+          : mFunc(std::forward<Func>(aFunc)),
+            mArgs(std::forward<Args>(aArgs)...)
+        {
+        }
+
+        void callFunc()
+        {
+            detail::invoke(std::move(mFunc), std::move(std::get<S>(mArgs)) ...);
+        }
+    };
+
+//  Allow construction of threads without exposing implementation.
+    class ThreadIdTool;
+} //  Namespace "detail"
+
+class thread
+{
+public:
+    class id
+    {
+        DWORD mId = 0;
+        friend class thread;
+        friend class std::hash<id>;
+        friend class detail::ThreadIdTool;
+        explicit id(DWORD aId) noexcept : mId(aId){}
+    public:
+        id (void) noexcept = default;
+        friend bool operator==(id x, id y) noexcept {return x.mId == y.mId; }
+        friend bool operator!=(id x, id y) noexcept {return x.mId != y.mId; }
+        friend bool operator< (id x, id y) noexcept {return x.mId <  y.mId; }
+        friend bool operator<=(id x, id y) noexcept {return x.mId <= y.mId; }
+        friend bool operator> (id x, id y) noexcept {return x.mId >  y.mId; }
+        friend bool operator>=(id x, id y) noexcept {return x.mId >= y.mId; }
+
+        template<class _CharT, class _Traits>
+        friend std::basic_ostream<_CharT, _Traits>&
+        operator<<(std::basic_ostream<_CharT, _Traits>& __out, id __id)
+        {
+            if (__id.mId == 0)
+            {
+                return __out << "(invalid std::thread::id)";
+            }
+            else
+            {
+                return __out << __id.mId;
+            }
+        }
+    };
+private:
+    static constexpr HANDLE kInvalidHandle = nullptr;
+    static constexpr DWORD kInfinite = 0xffffffffl;
+    HANDLE mHandle;
+    id mThreadId;
+
+    template <class Call>
+    static unsigned __stdcall threadfunc(void* arg)
+    {
+        std::unique_ptr<Call> call(static_cast<Call*>(arg));
+        call->callFunc();
+        return 0;
+    }
+
+    static unsigned int _hardware_concurrency_helper() noexcept
+    {
+        SYSTEM_INFO sysinfo;
+//    This is one of the few functions used by the library which has a nearly-
+//  equivalent function defined in earlier versions of Windows. Include the
+//  workaround, just as a reminder that it does exist.
+#if defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0501)
+        ::GetNativeSystemInfo(&sysinfo);
+#else
+        ::GetSystemInfo(&sysinfo);
+#endif
+        return sysinfo.dwNumberOfProcessors;
+    }
+public:
+    typedef HANDLE native_handle_type;
+    id get_id() const noexcept {return mThreadId;}
+    native_handle_type native_handle() const {return mHandle;}
+    thread(): mHandle(kInvalidHandle), mThreadId(){}
+
+    thread(thread&& other)
+    :mHandle(other.mHandle), mThreadId(other.mThreadId)
+    {
+        other.mHandle = kInvalidHandle;
+        other.mThreadId = id{};
+    }
+
+    thread(const thread &other)=delete;
+
+    template<class Func, typename... Args>
+    explicit thread(Func&& func, Args&&... args) : mHandle(), mThreadId()
+    {
+        using ArgSequence = typename detail::GenIntSeq<sizeof...(Args)>::type;
+        using Call = detail::ThreadFuncCall<Func, ArgSequence, Args...>;
+        auto call = new Call(
+            std::forward<Func>(func), std::forward<Args>(args)...);
+        unsigned id_receiver;
+        auto int_handle = _beginthreadex(NULL, 0, threadfunc<Call>,
+            static_cast<LPVOID>(call), 0, &id_receiver);
+        if (int_handle == 0)
+        {
+            mHandle = kInvalidHandle;
+            int errnum = errno;
+            delete call;
+//  Note: Should only throw EINVAL, EAGAIN, EACCES
+            throw std::system_error(errnum, std::generic_category());
+        } else {
+            mThreadId.mId = id_receiver;
+            mHandle = reinterpret_cast<HANDLE>(int_handle);
+        }
+    }
+
+    bool joinable() const {return mHandle != kInvalidHandle;}
+
+//    Note: Due to lack of synchronization, this function has a race condition
+//  if called concurrently, which leads to undefined behavior. The same applies
+//  to all other member functions of this class, but this one is mentioned
+//  explicitly.
+    void join()
+    {
+        using namespace std;
+        if (get_id() == id(GetCurrentThreadId()))
+            throw system_error(make_error_code(errc::resource_deadlock_would_occur));
+        if (mHandle == kInvalidHandle)
+            throw system_error(make_error_code(errc::no_such_process));
+        if (!joinable())
+            throw system_error(make_error_code(errc::invalid_argument));
+        WaitForSingleObject(mHandle, kInfinite);
+        CloseHandle(mHandle);
+        mHandle = kInvalidHandle;
+        mThreadId = id{};
+    }
+
+    ~thread()
+    {
+        if (joinable())
+        {
+#ifndef NDEBUG
+            std::printf("Error: Must join() or detach() a thread before \
+destroying it.\n");
+#endif
+            std::terminate();
+        }
+    }
+    thread& operator=(const thread&) = delete;
+    thread& operator=(thread&& other) noexcept
+    {
+        if (joinable())
+        {
+#ifndef NDEBUG
+            std::printf("Error: Must join() or detach() a thread before \
+moving another thread to it.\n");
+#endif
+            std::terminate();
+        }
+        swap(std::forward<thread>(other));
+        return *this;
+    }
+    void swap(thread&& other) noexcept
+    {
+        std::swap(mHandle, other.mHandle);
+        std::swap(mThreadId.mId, other.mThreadId.mId);
+    }
+
+    static unsigned int hardware_concurrency() noexcept
+    {
+        static unsigned int cached = _hardware_concurrency_helper();
+        return cached;
+    }
+
+    void detach()
+    {
+        if (!joinable())
+        {
+            using namespace std;
+            throw system_error(make_error_code(errc::invalid_argument));
+        }
+        if (mHandle != kInvalidHandle)
+        {
+            CloseHandle(mHandle);
+            mHandle = kInvalidHandle;
+        }
+        mThreadId = id{};
+    }
+};
+
+namespace detail
+{
+    class ThreadIdTool
+    {
+    public:
+        static thread::id make_id (DWORD base_id) noexcept
+        {
+            return thread::id(base_id);
+        }
+    };
+} //  Namespace "detail"
+
+namespace this_thread
+{
+    inline thread::id get_id() noexcept
+    {
+        return detail::ThreadIdTool::make_id(GetCurrentThreadId());
+    }
+    inline void yield() noexcept {Sleep(0);}
+    template< class Rep, class Period >
+    void sleep_for( const std::chrono::duration<Rep,Period>& sleep_duration)
+    {
+        static constexpr DWORD kInfinite = 0xffffffffl;
+        using namespace std::chrono;
+        using rep = milliseconds::rep;
+        rep ms = duration_cast<milliseconds>(sleep_duration).count();
+        while (ms > 0)
+        {
+            constexpr rep kMaxRep = static_cast<rep>(kInfinite - 1);
+            auto sleepTime = (ms < kMaxRep) ? ms : kMaxRep;
+            Sleep(static_cast<DWORD>(sleepTime));
+            ms -= sleepTime;
+        }
+    }
+    template <class Clock, class Duration>
+    void sleep_until(const std::chrono::time_point<Clock,Duration>& sleep_time)
+    {
+        sleep_for(sleep_time-Clock::now());
+    }
+}
+} //  Namespace mingw_stdthread
+
+namespace std
+{
+//    Because of quirks of the compiler, the common "using namespace std;"
+//  directive would flatten the namespaces and introduce ambiguity where there
+//  was none. Direct specification (std::), however, would be unaffected.
+//    Take the safe option, and include only in the presence of MinGW's win32
+//  implementation.
+#if defined(__MINGW32__ ) && !defined(_GLIBCXX_HAS_GTHREADS)
+using mingw_stdthread::thread;
+//    Remove ambiguity immediately, to avoid problems arising from the above.
+//using std::thread;
+namespace this_thread
+{
+using namespace mingw_stdthread::this_thread;
+}
+#elif !defined(MINGW_STDTHREAD_REDUNDANCY_WARNING)  //  Skip repetition
+#define MINGW_STDTHREAD_REDUNDANCY_WARNING
+#pragma message "This version of MinGW seems to include a win32 port of\
+ pthreads, and probably already has C++11 std threading classes implemented,\
+ based on pthreads. These classes, found in namespace std, are not overridden\
+ by the mingw-std-thread library. If you would still like to use this\
+ implementation (as it is more lightweight), use the classes provided in\
+ namespace mingw_stdthread."
+#endif
+
+//    Specialize hash for this implementation's thread::id, even if the
+//  std::thread::id already has a hash.
+template<>
+struct hash<mingw_stdthread::thread::id>
+{
+    typedef mingw_stdthread::thread::id argument_type;
+    typedef size_t result_type;
+    size_t operator() (const argument_type & i) const noexcept
+    {
+        return i.mId;
+    }
+};
+}
+#endif // WIN32STDTHREAD_H

sysconfig.h

@@ -426,9 +426,14 @@ extern "C" {
 #include <new>
 
 #if CAP_THREAD
+#if WINDOWS
+#include "mingw.thread.h"
+#include "mingw.mutex.h"
+#else
 #include <thread>
 #include <mutex>
 #endif
+#endif
 
 #ifdef USE_UNORDERED_MAP
 #include <unordered_map>