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diff --git a/boost/fiber/detail/thread_barrier.hpp b/boost/fiber/detail/thread_barrier.hpp
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+++ b/boost/fiber/detail/thread_barrier.hpp
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+
+//          Copyright Oliver Kowalke 2013.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_FIBER_DETAIL_THREAD_BARRIER_H
+#define BOOST_FIBER_DETAIL_THREAD_BARRIER_H
+
+#include <cstddef>
+#include <condition_variable>
+#include <mutex>
+
+#include <boost/assert.hpp>
+#include <boost/config.hpp>
+
+#include <boost/fiber/detail/config.hpp>
+
+#ifdef BOOST_HAS_ABI_HEADERS
+# include BOOST_ABI_PREFIX
+#endif
+
+namespace boost {
+namespace fibers {
+namespace detail {
+
+class thread_barrier {
+private:
+	std::size_t             initial_;
+	std::size_t             current_;
+	bool                    cycle_{ true };
+    std::mutex              mtx_{};
+    std::condition_variable cond_{};
+
+public:
+	explicit thread_barrier( std::size_t initial) :
+        initial_{ initial },
+        current_{ initial_ } {
+        BOOST_ASSERT ( 0 != initial);
+    }
+
+    thread_barrier( thread_barrier const&) = delete;
+    thread_barrier & operator=( thread_barrier const&) = delete;
+
+    bool wait() {
+        std::unique_lock< std::mutex > lk( mtx_);
+        const bool cycle = cycle_;
+        if ( 0 == --current_) {
+            cycle_ = ! cycle_;
+            current_ = initial_;
+            lk.unlock(); // no pessimization
+            cond_.notify_all();
+            return true;
+        } else {
+            cond_.wait( lk, [&](){ return cycle != cycle_; });
+        }
+        return false;
+    }
+};
+
+}}}
+
+#endif // BOOST_FIBER_DETAIL_THREAD_BARRIER_H