注意

使用system创建的共享内存，使用普通用户读取，创建时要设置权限 。

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permissions ps;
ps.set_unrestricted(); // 0666

使用shared_memory_object创建的共享内存不会随着对象的释放而删除。

使用windows_shared_memory创建的共享内存会随着对象的释放而删除，并且跨用户读取时，共享对象名前面需要加上"Global\\"表名是全局共享内存。

代码

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#include <boost/interprocess/shared_memory_object.hpp>  
#include <boost/interprocess/mapped_region.hpp>  
#include <boost/interprocess/windows_shared_memory.hpp>  

#define  USE_WIN_SHARE_MEMORY 0

// 创建
bool ShareMemory::CreateShare(const std::string& key, const std::string& value)
{
    using namespace boost::interprocess;
    try
    {
#if USE_WIN_SHARE_MEMORY
        permissions ps;
        ps.set_unrestricted(); // 0666 
        m_impl->wsm = std::make_shared<windows_shared_memory>(boost::interprocess::open_or_create, key.c_str(), read_write, value.length() + 1, ps);
        boost::interprocess::mapped_region region(*m_impl->wsm, read_write);
        std::memset(region.get_address(), 0, region.get_size());
        std::memcpy(region.get_address(), value.c_str(), value.length());
#else
        permissions ps;
        ps.set_unrestricted(); // 0666 
        shared_memory_object smo(boost::interprocess::open_or_create, key.c_str(), read_write, ps);
        smo.truncate(value.length() + 1);
        boost::interprocess::mapped_region region(smo, read_write);
        std::memset(region.get_address(), 0, region.get_size());
        std::memcpy(region.get_address(), value.c_str(), value.length());

#endif 
        return true;
    }
    catch (std::exception& e)
    {
        LOG_ERROR("open or create share memory error %s! %s, %s", e.what(), key.c_str(), value.c_str());
        return false;
    }
    return false;
}
// 读取
bool ShareMemory::ReadShare(const std::string& key, std::string& value)
{
    using namespace boost::interprocess; 
    try
    {
#if USE_WIN_SHARE_MEMORY
        m_impl->wsm = std::make_shared<windows_shared_memory>(open_only, key.c_str(), read_only);
        mapped_region region(*m_impl->wsm, read_only);
        char* port = static_cast<char*>(region.get_address());
        value = port;
        return true;
#else
        boost::interprocess::shared_memory_object shm(boost::interprocess::open_only, key.c_str(), boost::interprocess::read_only);
        boost::interprocess::mapped_region region(shm, boost::interprocess::read_only);
        char* port = static_cast<char*>(region.get_address());
        value = port;

#endif 
        return true;
    }
    catch (std::exception& e)
    {
        LOG_ERROR("read share memory error %s! %s, %s", e.what(), key.c_str(), value.c_str());
        return false;
    }
    return false;
}