mirror of
https://github.com/zeromq/libzmq.git
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231 lines
7.7 KiB
C++
231 lines
7.7 KiB
C++
/*
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Copyright (c) 2007-2015 Contributors as noted in the AUTHORS file
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This file is part of libzmq, the ZeroMQ core engine in C++.
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libzmq is free software; you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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As a special exception, the Contributors give you permission to link
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this library with independent modules to produce an executable,
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regardless of the license terms of these independent modules, and to
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copy and distribute the resulting executable under terms of your choice,
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provided that you also meet, for each linked independent module, the
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terms and conditions of the license of that module. An independent
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module is a module which is not derived from or based on this library.
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If you modify this library, you must extend this exception to your
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version of the library.
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libzmq is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ZMQ_ATOMIC_COUNTER_HPP_INCLUDED__
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#define __ZMQ_ATOMIC_COUNTER_HPP_INCLUDED__
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#include "stdint.hpp"
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#include "platform.hpp"
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#if defined ZMQ_FORCE_MUTEXES
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#define ZMQ_ATOMIC_COUNTER_MUTEX
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#elif defined ZMQ_HAVE_ATOMIC_INTRINSICS
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#define ZMQ_ATOMIC_COUNTER_INTRINSIC
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#elif (defined ZMQ_CXX11 && defined __cplusplus && __cplusplus >= 201103L)
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#define ZMQ_ATOMIC_COUNTER_CXX11
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#elif (defined __i386__ || defined __x86_64__) && defined __GNUC__
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#define ZMQ_ATOMIC_COUNTER_X86
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#elif defined __ARM_ARCH_7A__ && defined __GNUC__
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#define ZMQ_ATOMIC_COUNTER_ARM
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#elif defined ZMQ_HAVE_WINDOWS
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#define ZMQ_ATOMIC_COUNTER_WINDOWS
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#elif (defined ZMQ_HAVE_SOLARIS || defined ZMQ_HAVE_NETBSD)
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#define ZMQ_ATOMIC_COUNTER_ATOMIC_H
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#elif defined __tile__
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#define ZMQ_ATOMIC_COUNTER_TILE
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#else
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#define ZMQ_ATOMIC_COUNTER_MUTEX
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#endif
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#if defined ZMQ_ATOMIC_COUNTER_MUTEX
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#include "mutex.hpp"
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#elif defined ZMQ_ATOMIC_COUNTER_CXX11
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#include <atomic>
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#elif defined ZMQ_ATOMIC_COUNTER_WINDOWS
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#include "windows.hpp"
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#elif defined ZMQ_ATOMIC_COUNTER_ATOMIC_H
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#include <atomic.h>
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#elif defined ZMQ_ATOMIC_COUNTER_TILE
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#include <arch/atomic.h>
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#endif
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namespace zmq
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{
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// This class represents an integer that can be incremented/decremented
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// in atomic fashion.
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class atomic_counter_t
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{
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public:
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typedef uint32_t integer_t;
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inline atomic_counter_t (integer_t value_ = 0) :
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value (value_)
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{
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}
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inline ~atomic_counter_t ()
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{
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}
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// Set counter value (not thread-safe).
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inline void set (integer_t value_)
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{
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value = value_;
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}
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// Atomic addition. Returns the old value.
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inline integer_t add (integer_t increment_)
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{
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integer_t old_value;
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#if defined ZMQ_ATOMIC_COUNTER_WINDOWS
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old_value = InterlockedExchangeAdd ((LONG*) &value, increment_);
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#elif defined ZMQ_ATOMIC_COUNTER_INTRINSIC
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old_value = __atomic_fetch_add(&value, increment_, __ATOMIC_ACQ_REL);
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#elif defined ZMQ_ATOMIC_COUNTER_CXX11
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old_value = value.fetch_add(increment_, std::memory_order_acq_rel);
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#elif defined ZMQ_ATOMIC_COUNTER_ATOMIC_H
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integer_t new_value = atomic_add_32_nv (&value, increment_);
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old_value = new_value - increment_;
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#elif defined ZMQ_ATOMIC_COUNTER_TILE
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old_value = arch_atomic_add (&value, increment_);
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#elif defined ZMQ_ATOMIC_COUNTER_X86
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__asm__ volatile (
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"lock; xadd %0, %1 \n\t"
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: "=r" (old_value), "=m" (value)
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: "0" (increment_), "m" (value)
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: "cc", "memory");
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#elif defined ZMQ_ATOMIC_COUNTER_ARM
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integer_t flag, tmp;
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__asm__ volatile (
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" dmb sy\n\t"
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"1: ldrex %0, [%5]\n\t"
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" add %2, %0, %4\n\t"
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" strex %1, %2, [%5]\n\t"
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" teq %1, #0\n\t"
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" bne 1b\n\t"
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" dmb sy\n\t"
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: "=&r"(old_value), "=&r"(flag), "=&r"(tmp), "+Qo"(value)
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: "Ir"(increment_), "r"(&value)
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: "cc");
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#elif defined ZMQ_ATOMIC_COUNTER_MUTEX
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sync.lock ();
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old_value = value;
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value += increment_;
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sync.unlock ();
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#else
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#error atomic_counter is not implemented for this platform
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#endif
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return old_value;
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}
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// Atomic subtraction. Returns false if the counter drops to zero.
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inline bool sub (integer_t decrement)
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{
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#if defined ZMQ_ATOMIC_COUNTER_WINDOWS
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LONG delta = - ((LONG) decrement);
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integer_t old = InterlockedExchangeAdd ((LONG*) &value, delta);
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return old - decrement != 0;
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#elif defined ZMQ_ATOMIC_COUNTER_INTRINSIC
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integer_t nv = __atomic_sub_fetch(&value, decrement, __ATOMIC_ACQ_REL);
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return nv != 0;
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#elif defined ZMQ_ATOMIC_COUNTER_CXX11
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integer_t old = value.fetch_sub(decrement, std::memory_order_acq_rel);
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return old - decrement != 0;
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#elif defined ZMQ_ATOMIC_COUNTER_ATOMIC_H
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int32_t delta = - ((int32_t) decrement);
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integer_t nv = atomic_add_32_nv (&value, delta);
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return nv != 0;
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#elif defined ZMQ_ATOMIC_COUNTER_TILE
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int32_t delta = - ((int32_t) decrement);
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integer_t nv = arch_atomic_add (&value, delta);
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return nv != 0;
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#elif defined ZMQ_ATOMIC_COUNTER_X86
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integer_t oldval = -decrement;
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volatile integer_t *val = &value;
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__asm__ volatile ("lock; xaddl %0,%1"
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: "=r" (oldval), "=m" (*val)
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: "0" (oldval), "m" (*val)
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: "cc", "memory");
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return oldval != decrement;
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#elif defined ZMQ_ATOMIC_COUNTER_ARM
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integer_t old_value, flag, tmp;
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__asm__ volatile (
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" dmb sy\n\t"
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"1: ldrex %0, [%5]\n\t"
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" sub %2, %0, %4\n\t"
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" strex %1, %2, [%5]\n\t"
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" teq %1, #0\n\t"
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" bne 1b\n\t"
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" dmb sy\n\t"
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: "=&r"(old_value), "=&r"(flag), "=&r"(tmp), "+Qo"(value)
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: "Ir"(decrement), "r"(&value)
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: "cc");
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return old_value - decrement != 0;
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#elif defined ZMQ_ATOMIC_COUNTER_MUTEX
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sync.lock ();
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value -= decrement;
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bool result = value ? true : false;
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sync.unlock ();
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return result;
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#else
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#error atomic_counter is not implemented for this platform
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#endif
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}
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inline integer_t get () const
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{
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return value;
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}
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private:
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#if defined ZMQ_ATOMIC_COUNTER_CXX11
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std::atomic<integer_t> value;
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#else
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volatile integer_t value;
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#endif
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#if defined ZMQ_ATOMIC_COUNTER_MUTEX
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mutex_t sync;
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#endif
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#if ! defined ZMQ_ATOMIC_COUNTER_CXX11
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atomic_counter_t (const atomic_counter_t&);
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const atomic_counter_t& operator = (const atomic_counter_t&);
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#endif
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};
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}
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// Remove macros local to this file.
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#undef ZMQ_ATOMIC_COUNTER_MUTEX
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#undef ZMQ_ATOMIC_COUNTER_INTRINSIC
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#undef ZMQ_ATOMIC_COUNTER_CXX11
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#undef ZMQ_ATOMIC_COUNTER_X86
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#undef ZMQ_ATOMIC_COUNTER_ARM
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#undef ZMQ_ATOMIC_COUNTER_WINDOWS
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#undef ZMQ_ATOMIC_COUNTER_ATOMIC_H
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#undef ZMQ_ATOMIC_COUNTER_TILE
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#endif
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