请教类实例指针的问题，急急急！！！

Cion

我今天遇到一个很棘手的问题，检查了一整天了，但一直查不出问题所在，所以得请教高手了：
    ：就是在一个成员函数中调用m_pComparator->CompCounter2Self()，执行之前（p *m_pComparator ）内容都有，紧接着一步，这个调用之后，我要判断执行成功与否，就调用（if (m_pComparator->GetErrMsg() != string(""))），奇怪的是，这个时候（p *m_pComparator ）发现m_pComparator 里面的成员变量和成员函数均被初始化了（见下面的结果）。所以每次执行m_pComparator->GetErrMsg() 都会coredump。这是什么原因呢？怎么能导致m_pComparator 被初始化呢？

    给指点一下。不胜感激！！！！！！！！
    m_pComparator->CompCounter2Self();
    if (m_pComparator->GetErrMsg() != string(""))
    {
        m_strErrMsg = m_pComparator->GetErrMsg();
    }

482         m_pComparator->CompCounter2Self();
(gdb) p *m_pComparator     
$1 = {m_sCityCode = "778", m_iServiceKind = 0, m_iMonth = 8, m_iDay = 5, m_iTopic = 1, m_iSource = 0, m_bIsCounterNumber = true,
  m_iCallDateErr = 6, m_iDurationErr = 3, m_pSelfCallDetail = 0x0, m_pCounterCallDetail = 0x0, m_pSelfTree = 0x8000000100065d20,
  m_pCounterTree = 0x8000000100065ea8, m_pCompareIndb = 0x800000010006f648, m_pCurrCallDetail = 0x0,
  m_strRunningState = {<class std::allocator<char>> = {<No data fields>}, static npos = 18446744073709551615, static __nullref = {
      __ref_hdr_ = {__mutex_ = {<class __rw::__rw_mutex_base> = {_C_mutex = {<No data fields>}}, <No data fields>}, __refs_ = 1,
        __capacity_ = 0, __nchars_ = 0}, __eos_char_ = 0 '\000'}, _C_data = 0x800003fffe8923f8 ""},
  m_strErrMsg = {<class std::allocator<char>> = {<No data fields>}, static npos = 18446744073709551615, static __nullref = {
      __ref_hdr_ = {__mutex_ = {<class __rw::__rw_mutex_base> = {_C_mutex = {<No data fields>}}, <No data fields>}, __refs_ = 1,
        __capacity_ = 0, __nchars_ = 0}, __eos_char_ = 0 '\000'}, _C_data = 0x800003fffe8923f8 ""},
  m_pIndbLog = 0x0, __vfp = 0x800000010000bd58}
(gdb) p m_pComparator->GetErrMsg()
$2 = {<class std::allocator<char>> = {<No data fields>}, static npos = 18446744073709551615, static __nullref = {__ref_hdr_ = {
      __mutex_ = {<class __rw::__rw_mutex_base> = {_C_mutex = {<No data fields>}}, <No data fields>}, __refs_ = 1,
      __capacity_ = 0, __nchars_ = 0}, __eos_char_ = 0 '\000'}, _C_data = 0x800003fffe8923f8 ""}

顺利执行之后：
483         if (m_pComparator->GetErrMsg() != string(""))
(gdb) p *m_pComparator
$3 = {m_sCityCode = "\000\000", m_iServiceKind = 0, m_iMonth = 0, m_iDay = 0, m_iTopic = 0, m_iSource = 0,
  m_bIsCounterNumber = false, m_iCallDateErr = 0, m_iDurationErr = 0, m_pSelfCallDetail = 0x0, m_pCounterCallDetail = 0x0,
  m_pSelfTree = 0x0, m_pCounterTree = 0x0, m_pCompareIndb = 0x0, m_pCurrCallDetail = 0x0,
  m_strRunningState = {<class std::allocator<char>> = {<No data fields>}, static npos = 18446744073709551615, static __nullref = {
      __ref_hdr_ = {__mutex_ = {<class __rw::__rw_mutex_base> = {_C_mutex = {<No data fields>}}, <No data fields>}, __refs_ = 1,
        __capacity_ = 0, __nchars_ = 0}, __eos_char_ = 0 '\000'}, _C_data = 0x0},
  m_strErrMsg = {<class std::allocator<char>> = {<No data fields>}, static npos = 18446744073709551615, static __nullref = {
      __ref_hdr_ = {__mutex_ = {<class __rw::__rw_mutex_base> = {_C_mutex = {<No data fields>}}, <No data fields>}, __refs_ = 1,
        __capacity_ = 0, __nchars_ = 0}, __eos_char_ = 0 '\000'}, _C_data = 0x0}, m_pIndbLog = 0x0, __vfp = 0x0}

Program received signal SIGSEGV, Segmentation fault.
0x40000000000dd880 in std::basic_string<char,std::char_traits<char>,std::allocator<char>>::basic_string<char,std::char_traits<char>,std::allocator<char>>+0x64 ()
(gdb)

prc

如果CompCounter2Self和GetErrMsg都没问题那么

1. 
   
2.     m_pComparator->CompCounter2Self();
   
3.     if (m_pComparator->GetErrMsg() != string(""))
   
4.     {
   
5.         m_strErrMsg = m_pComparator->GetErrMsg();
   
6.     }
   

复制代码

就不会有问题

可以参考下面的例子

1. 
   
2. #include <stdio.h>
   
3. 
   
4. #include <vector>
   
5. #include <string>
   
6. #include <iostream>
   
7. using namespace std;
   
8. 
   
9. 
   
10. class A {
    
11.        
    
12. public:       
    
13.         void CompCounter2Self() {}
    
14.        
    
15.         string GetErrMsg()
    
16.         {
    
17.                 return string("error");
    
18.         }
    
19. };
    
20. 
    
21. 
    
22. int main()
    
23. {
    
24.         A *m_pComparator = new A;
    
25.         string m_strErrMsg;
    
26.        
    
27.         m_pComparator->CompCounter2Self();
    
28.     if (m_pComparator->GetErrMsg() != string(""))
    
29.     {
    
30.         m_strErrMsg = m_pComparator->GetErrMsg();
    
31.         
    
32.         cout << m_strErrMsg << endl;
    
33.     }
    
34. }
    
35. 
    
36. 
    

复制代码

出coredump，我想可能是在函数CompCounter2Self里做了什么不应该做的操作...

Cion

出coredump，我想可能是在函数CompCounter2Self里做了什么不应该做的操作...

我想是在这里。
怀疑是m_pComparator->CompCounter2Self()，中的memset(m_pkIndbBatch, 0x0, g_iInsertBatchNum * sizeof(KCompareIndb));
覆盖了其他内存。

我注释掉就好了。
而m_pkIndbBatch = new KCompareIndb[g_iInsertBatchNum];使用之前memset有问题吗？没看出来问题。

prc

不是先new再memset吗