/*
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* =====================================================================================
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*
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* Filename: shm.h
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*
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* Description:
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*
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* Version: 1.0
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* Created: 2021年03月22日 16时19分21秒
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* Revision: none
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* Compiler: gcc
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*
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* Author: Li Chao (),
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* Organization:
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*
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* =====================================================================================
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*/
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#ifndef SHM_6CHO6D6C
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#define SHM_6CHO6D6C
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#include "log.h"
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#include <atomic>
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#include <boost/interprocess/managed_shared_memory.hpp>
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#include <boost/interprocess/sync/interprocess_mutex.hpp>
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#include <boost/noncopyable.hpp>
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#include <thread>
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namespace bhome_shm
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{
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using namespace boost::interprocess;
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typedef managed_shared_memory mshm_t;
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class MutexWithPidCheck
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{
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typedef boost::interprocess::interprocess_mutex MutexT;
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static pid_t pid()
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{
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static pid_t val = getpid();
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return val;
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}
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static bool Killed(pid_t pid)
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{
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char buf[64] = {0};
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snprintf(buf, sizeof(buf) - 1, "/proc/%d/stat", pid);
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return access(buf, F_OK) != 0;
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}
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bool PidCas(pid_t exp, pid_t val) { return pid_.compare_exchange_strong(exp, val); }
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MutexT mutex_;
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std::atomic<pid_t> pid_;
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public:
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typedef MutexT::internal_mutex_type internal_mutex_type;
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const internal_mutex_type &internal_mutex() const { return mutex_.internal_mutex(); }
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internal_mutex_type &internal_mutex() { return mutex_.internal_mutex(); }
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MutexWithPidCheck() :
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pid_(0) {}
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bool try_lock()
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{
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bool r = false;
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if (mutex_.try_lock()) {
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auto old = pid_.load();
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r = PidCas(old, pid());
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} else {
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auto old = pid_.load();
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if (Killed(old)) {
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r = PidCas(old, pid());
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if (r) {
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LOG_DEBUG() << "PidCheck captured pid " << old << " -> " << pid();
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}
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}
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}
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return r;
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}
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void lock()
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{
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while (!try_lock()) {
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std::this_thread::yield();
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}
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}
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void unlock()
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{
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auto old = pid_.load();
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if (old == pid()) {
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mutex_.unlock();
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}
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}
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};
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typedef interprocess_mutex Mutex;
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typedef scoped_lock<Mutex> Guard;
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// typedef robust::Guard<Mutex> Guard;
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class SharedMemory : public mshm_t
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{
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std::string name_;
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Mutex *pmutex_ = 0;
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static permissions AllowAll()
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{
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permissions perm;
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perm.set_unrestricted();
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return perm;
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}
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void Swap(SharedMemory &a);
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public:
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static bool Remove(const std::string &name) { return shared_memory_object::remove(name.c_str()); }
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SharedMemory(const std::string &name, const uint64_t size);
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~SharedMemory();
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std::string name() const { return name_; }
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bool Remove() { return Remove(name()); }
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template <class T, class... Params>
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T *FindOrCreate(const std::string &name, Params &&...params)
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{
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return find_or_construct<T>(name.c_str(), std::nothrow)(std::forward<decltype(params)>(params)...);
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}
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template <class T, class... Params>
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T *Create(const std::string &name, Params &&...params)
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{
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return construct<T>(name.c_str(), std::nothrow)(std::forward<decltype(params)>(params)...);
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}
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void *Alloc(const size_t size)
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{
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Guard lock(*pmutex_);
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return allocate(size, std::nothrow);
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}
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void Dealloc(void *p)
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{
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Guard lock(*pmutex_);
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if (p) { deallocate(p); }
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}
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template <class T>
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void Dealloc(offset_ptr<T> ptr) { return Dealloc(ptr.get()); }
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template <class T, class... Params>
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T *New(Params &&...params)
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{
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Guard lock(*pmutex_);
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return construct<T>(anonymous_instance, std::nothrow)(std::forward<decltype(params)>(params)...);
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}
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template <class T>
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void Delete(T *p)
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{
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Guard lock(*pmutex_);
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if (p) { destroy_ptr<T>(p); };
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}
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template <class T>
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void Delete(offset_ptr<T> p) { Delete(p.get()); }
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template <class T>
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T *Find(const std::string &name) { return find<T>(name.c_str()).first; }
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};
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template <class D>
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using Allocator = allocator<D, SharedMemory::segment_manager>;
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template <class D>
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using Deleter = deleter<D, SharedMemory::segment_manager>;
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template <class D>
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using SharedPtr = shared_ptr<D, Allocator<void>, Deleter<D>>;
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// ShmObject manages an object in shared memory, but ShmObject itself is not in shared memory.
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template <class T>
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class ShmObject : private boost::noncopyable
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{
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static std::string ObjName(const std::string &name) { return "obj" + name; }
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public:
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typedef T Data;
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typedef SharedMemory ShmType;
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ShmType &shm() const { return shm_; }
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template <class... Params>
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ShmObject(ShmType &segment, const std::string &name, Params &&...t) :
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shm_(segment), name_(name)
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{
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pdata_ = shm_.FindOrCreate<Data>(ObjName(name_), std::forward<decltype(t)>(t)...);
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if (!IsOk()) {
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throw("Error: Not enough memory, can not allocate \"" + name_ + "\"");
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}
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}
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template <class... Params>
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ShmObject(ShmType &segment, const bool create_or_else_find, const std::string &name, Params &&...t) :
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shm_(segment), name_(name)
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{
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if (create_or_else_find) {
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pdata_ = shm_.Create<Data>(ObjName(name_), std::forward<decltype(t)>(t)...);
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} else {
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pdata_ = shm_.Find<Data>(ObjName(name_));
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}
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}
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ShmObject(const int64_t offset, ShmType &segment, const std::string &name) :
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shm_(segment), name_(name)
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{
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pdata_ = reinterpret_cast<Data *>(Addr(shm_.get_address()) + offset);
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}
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bool IsOk() const { return pdata_; }
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static bool Remove(SharedMemory &shm, const std::string &name) { return shm.destroy<Data>(ObjName(name).c_str()); }
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static Data *Find(SharedMemory &shm, const std::string &name) { return shm.Find<Data>(ObjName(name)); }
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Data *Find(const std::string &name) { return Find(shm_, ObjName(name)); }
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virtual ~ShmObject() {}
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std::string name() const { return name_; }
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Data *data() { return pdata_; }
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const Data *data() const { return pdata_; }
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int64_t offset() const { return Addr(pdata_) - Addr(shm_.get_address()); }
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Data *operator->() { return data(); }
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const Data *operator->() const { return data(); }
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bool Remove() { return Remove(shm_, name_); }
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private:
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static int64_t Addr(const void *p) { return reinterpret_cast<int64_t>(p); }
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ShmType &shm_;
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std::string name_;
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Data *pdata_ = nullptr;
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};
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} // namespace bhome_shm
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#endif // end of include guard: SHM_6CHO6D6C
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