C++怪事：一个类只能new一次，第二次就报 Bad permissions for mapped region at address（百度、qq几天无果）

[leinchu]

我会c，完全不会c++，下载别人c++代码学习。

原本那个类代码是这样的：

CMailBox::CMailBox(uint16_t uid, EFDTYPE fdtype, const char* pszAddr, uint16_t unPort)
    : m_bConnected(false), m_fd(0), m_fdType(fdtype), m_connectdTime(0),
      m_serverName(pszAddr), m_serverPort(unPort), m_unRecvBuffLen(0), m_id(uid),
      m_unServerMbType(SERVER_NONE), m_uAuthz(MAILBOX_CLIENT_UNAUTHZ), m_nSendPos(0), m_bDeleteFlag(false)
{
    //m_connectdTime = time(NULL);
    m_lastTickTime = m_connectdTime;

    if(fdtype == FD_TYPE_MAILBOX)
    {
        m_timeout = OTHERSERVER_TIMEOUT;
    }
    else
    {
        m_timeout = CLIENT_TIMEOUT;
    }
}

我这样调用：

CMailBox* mb0 = new CMailBox(7, FD_TYPE_MAILBOX, "127.0.0.1", 8002);
CMailBox* mb1 = new CMailBox(7, FD_TYPE_MAILBOX, "127.0.0.1", 8003);

就在CMailBox* mb1 这个报错，但第一个mb0没有报错：

==5344== 
==5344== Process terminating with default action of signal 11 (SIGSEGV)
==5344==  Bad permissions for mapped region at address 0x5000001
==5344==    at 0x4A54E7: CMailBox::CMailBox(unsigned short, mogo::EFDTYPE, char const*, unsigned short) (mailbox.cpp:27)

把构造函数直接改简单为：

CMailBox::CMailBox()
{
	cout << "Constructor called" << endl;
	//this->initValues(1, FD_TYPE_SERVER, "127.0.0.1", 8001);
	cout << "Constructor ended" << endl;
}

调用为：

CMailBox* mb0 = new CMailBox();
CMailBox* mb1 = new CMailBox();

同样是就在CMailBox* mb1 这个报错，但第一个mb0没有报错，错误内容不一样了：

==64250== 
==64250== Process terminating with default action of signal 11 (SIGSEGV)
==64250==  Bad permissions for mapped region at address 0x5000011
==64250==    at 0x3F7DC9C08B: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string() (in /usr/lib64/libstdc++.so.6.0.13)
==64250==    by 0x4A550A: CMailBox::CMailBox() (mailbox.cpp:32)

百度了很多，加了好几个qq群，大家也给了各种方法，就是解决不了。。。
哭了，求帮助！

[luoyely]

https://www.baidu.com/link?url=k5ju6gfrkJtesvdTu8T2qtxzF5a0lHG4BQkVsZoGl2kDlZmffrtVLAxcbFHkkIbRBfC2IdOlOkTldG1jz2K0UGG2dtbmIRkxMMY_JGI7oanCe2eLJZVOSG5MOVkKukOIYEdilPF__9ZWJeULxeApka&wd=&eqid=be40d5e20031ee08000000035d5f9260

[luoyely]

引用 1 楼 luoyely 的回复:

https://www.baidu.com/link?url=k5ju6gfrkJtesvdTu8T2qtxzF5a0lHG4BQkVsZoGl2kDlZmffrtVLAxcbFHkkIbRBfC2IdOlOkTldG1jz2K0UGG2dtbmIRkxMMY_JGI7oanCe2eLJZVOSG5MOVkKukOIYEdilPF__9ZWJeULxeApka&wd=&eqid=be40d5e20031ee08000000035d5f9260

这个也是百度到的，你可以把源码发一下看看

[飞雪蝶映]

应该是继承类有什么限制，或者是有些必要参数不能用一样，可能关联到内核中比较唯一的东西。

[NorZ]

类的定义发来看看？

[leinchu]

void * CMailBox::operator new(size_t size)
{
    m_lock.Lock();

    if (NULL == memPool)
    {
        expandMemoryPool();
    }

    MemoryPool *head = memPool;
    memPool = head->next;

    m_lock.Unlock();

    //LogDebug("CMailBox new", "");

    return memPool;//这里不对，应该返回 return head;
}