C++构造函数中的损坏

Question

我正面临着构造器中的损坏。有人能帮帮我吗？

    2873            int rc = _db->fetch_custom_sql_query(rwc.GetQueryName(),selectConstruct, HandleCustomSqlQueryResponse, (void*)&holder);
    (gdb) p selectConstruct
    $1 = {distinct = false, colsToBeSelected = {cols = {<std::_Vector_base<dbCol,     std::allocator<dbCol> >> = {_M_impl = {<std::allocator<dbCol>> = {<__gnu_cxx::new_allocator<dbCol>> = {<No data fields>}, <No data fields>}, _M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0}}, <No data fields>}}, tableName = {static npos = 18446744073709551615, _M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x3dd36f32d8 ""}}, where = {whereExprs = {<std::_Vector_base<whereExpr, std::allocator<whereExpr> >> = {_M_impl = {<std::allocator<whereExpr>> = {<__gnu_cxx::new_allocator<whereExpr>> = {<No data fields>}, <No data fields>}, _M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0}}, <No data fields>}, ops = {<std::_Vector_base<adjoinOperator, std::allocator<adjoinOperator> >> = {_M_impl = {<std::allocator<adjoinOperator>> = {<__gnu_cxx::new_allocator<adjoinOperator>> = {<No data fields>}, <No data fields>}, _M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0}}, <No data fields>}, namespaceCounts = {<std::_Vector_base<unsigned int, std::allocator<unsigned int> >> = {_M_impl = {<std::allocator<unsigned int>> = {<__gnu_cxx::new_allocator<unsigned int>> = {<No data fields>}, <No data fields>}, _M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0}}, <No data fields>}, useAsON = false}, groupBy = {cols = {<std::_Vector_base<dbCol, std::allocator<dbCol> >> = {_M_impl = {<std::allocator<dbCol>> = {<__gnu_cxx::new_allocator<dbCol>> = {<No data fields>}, <No data fields>}, _M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0}}, <No data fields>}}, orders = {orders = {<std::_Vector_base<orderingTerm, std::allocator<orderingTerm> >> = {_M_impl = {<std::allocator<orderingTerm>> = {<__gnu_cxx::new_allocator<orderingTerm>> = {<No data fields>}, <No data fields>}, _M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0}}, <No data fields>}}, limit = -1}
   (gdb) stepi
    0x00007ffff0df9b49      2873            int rc = _db-   >fetch_custom_sql_query(rwc.GetQueryName(),selectConstruct, HandleCustomSqlQueryResponse, (void*)&holder);
   (gdb) stepi
   0x00007ffff0df9b50      2873            int rc = _db->fetch_custom_sql_query(rwc.GetQueryName(),selectConstruct, HandleCustomSqlQueryResponse, (void*)&holder);
   (gdb) stepi
   0x00007ffff0df9b53      2873            int rc = _db->fetch_custom_sql_query(rwc.GetQueryName(),selectConstruct, HandleCustomSqlQueryResponse, (void*)&holder);
  (gdb) stepi
   0x00007ffff0df9b5b      2873            int rc = _db->fetch_custom_sql_query(rwc.GetQueryName(),selectConstruct, HandleCustomSqlQueryResponse, (void*)&holder);
   (gdb) stepi
   0x00007ffff0df9b5e      2873            int rc = _db->fetch_custom_sql_query(rwc.GetQueryName(),selectConstruct, HandleCustomSqlQueryResponse, (void*)&holder);
   (gdb) stepi
    0x00007ffff0da8000 in simpleSelectConstruct::simpleSelectConstruct () from   /opt/OV/lbin/OpsAgt/libDMLSegment.so
   (gdb) stepi
   simpleSelectConstruct::simpleSelectConstruct (this=0x7fffdbffdbb0) at /home/parakkal/COLLABNET_11.10_NEW/hpsw-oa/AgentFramework/cpp/src/include/OpsAgt/DBsupports.h:170
   170     class simpleSelectConstruct{
   /include/OpsAgt/DBsupports.h:170
   170     class simpleSelectConstruct{
  (gdb) p *this
   $2 = {distinct = false, colsToBeSelected = {cols = {<std::_Vector_base<dbCol,   std::allocator<dbCol> >> = {_M_impl = {<std::allocator<dbCol>> =  {<__gnu_cxx::new_allocator<dbCol>> = {<No data fields>}, <No data fields>}, _M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0}}, <No data fields>}}, tableName = {static npos = 18446744073709551615, _M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x0}}, where = {whereExprs = {<std::_Vector_base<whereExpr, std::allocator<whereExpr> >> = {_M_impl = {<std::allocator<whereExpr>> = {<__gnu_cxx::new_allocator<whereExpr>> = {<No data fields>}, <No data fields>}, _M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0}}, <No data fields>}, ops = {<std::_Vector_base<adjoinOperator, std::allocator<adjoinOperator> >> = {_M_impl = {<std::allocator<adjoinOperator>> = {<__gnu_cxx::new_allocator<adjoinOperator>> = {<No data fields>}, <No data fields>}, _M_start = 0x0, _M_finish = 0x3dd34bd704, _M_end_of_storage = 0x7ffff7ca52b0}}, <No data fields>}, namespaceCounts = {<std::_Vector_base<unsigned int, std::allocator<unsigned int> >> = {_M_impl = {<std::allocator<unsigned int>> = {<__gnu_cxx::new_allocator<unsigned int>> = {<No data fields>}, <No data fields>}, _M_start = 0x7fffdbffe910, _M_finish = 0x6, _M_end_of_storage = 0x4e}}, <No data fields>}, useAsON = false}, groupBy = {cols = {<std::_Vector_base<dbCol, std::allocator<dbCol> >> = {_M_impl = {<std::allocator<dbCol>> = {<__gnu_cxx::new_allocator<dbCol>> = {<No data fields>}, <No data fields>}, _M_start = 0x7fffdbffe910, _M_finish = 0x0, _M_end_of_storage = 0x7ffff6f54d1f}}, <No data fields>}}, orders = {orders = {<std::_Vector_base<orderingTerm, std::allocator<orderingTerm> >> = {_M_impl = {<std::allocator<orderingTerm>> = {<__gnu_cxx::new_allocator<orderingTerm>> = {<No data fields>}, <No data fields>}, _M_start = 0x7ffff7ca52b0, _M_finish = 0x7ffff6f5584d, _M_end_of_storage = 0x5509f0}}, <No data fields>}}, limit = -603988688}
  (gdb) stepi

如果您在构造函数中看到上述限制已损坏，那么_M_start、_M_finish和_M_end_of_storage也是如此。simpleSelectConstruct类如下所示

class simpleSelectConstruct{

 public:
   DBSupportsInterface simpleSelectConstruct()
   {
      distinct=false;
      limit=-1;
   }
   bool distinct;
   dbCols colsToBeSelected;
   string tableName;
   whereConstruct where;
   dbCols groupBy;
   orderBy orders;
   int limit;
};

我已经在https://gcc.gnu.org/ml/gcc-help/2014-08/msg00104.html上发布了完整的信息

Answer 1

(gdb) stepi
0x00007ffff0df9b5e      2873            int rc =
_db->fetch_custom_sql_query(rwc.GetQueryName(),selectConstruct,HandleCustomSqlQueryResponse, (void*)&holder);
(gdb) stepi
0x00007ffff0da8000 in simpleSelectConstruct::simpleSelectConstruct ()
from /opt/OV/lbin/OpsAgt/libDMLSegment.so
(gdb) stepi
simpleSelectConstruct::simpleSelectConstruct (this=0x7fffdbffdbb0) 
[SNIP]
(gdb) p *this
[SNIP OUTPUT BEFORE CONSTRUCTOR RUNS]
(gdb) stepi
0x00007ffff0e11892      170     class simpleSelectConstruct{
(gdb) stepi
0x00007ffff0e11894      170     class simpleSelectConstruct{
(gdb) stepi
0x00007ffff0e11896      170     class simpleSelectConstruct{
(gdb) stepi
0x00007ffff0e11898      170     class simpleSelectConstruct{
(gdb) p *this
[SNIP OUTPUT DURING CONSTRUCTOR]
(gdb)
[END OF DEBUGGING SESSION]

我没有看到腐败的证据。我看到您打印出一个未损坏的变量selectConstruct，进入simpleSelectConstruct构造函数，打印即将构造的simpleSelectConstruct，执行四个步骤，然后打印只构造了一半的simpleSelectConstruct。(这两者都不是selectConstruct变量)。你有没有试着等到构造函数完成之后？

当构造函数开始时：

distinct = false
colsToBeSelected = 
    cols = ..._M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0 ...
tableName = ..._M_p = 0x0 ...
where = 
    whereExprs = ..._M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0...
    ops = ..._M_start = 0x0, _M_finish = 0x3dd34bd704, _M_end_of_storage = 0x7ffff7ca52b0...
    namespaceCounts = ..._M_start = 0x7fffdbffe910, _M_finish = 0x6, _M_end_of_storage = 0x4e...
    useAsON = false
groupBy = 
    cols = ..._M_start = 0x7fffdbffe910, _M_finish = 0x0, _M_end_of_storage = 0x7ffff6f54d1f...
orders = ..._M_start = 0x7ffff7ca52b0, _M_finish = 0x7ffff6f5584d, _M_end_of_storage = 0x5509f0...
limit = -603988688

在构造函数中执行了四个步骤后：

distinct = false
colsToBeSelected = 
    cols = ..._M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0 ...
tableName = ..._M_p = 0x0...
where = 
    whereExprs = ..._M_start = 0x0, _M_finish = 0x0, _M_end_of_storage = 0x0...
    ops = ..._M_start = 0x0, _M_finish = 0x3dd34bd704, _M_end_of_storage = 0x7ffff7ca52b0...
    namespaceCounts = ..._M_start = 0x7fffdbffe910, _M_finish = 0x6, _M_end_of_storage = 0x4e...
    useAsON = false
groupBy = 
    cols = ..._M_start = 0x7fffdbffe910, _M_finish = 0x0, _M_end_of_storage = 0x7ffff6f54d1f...
orders = ..._M_start = 0x7ffff7ca52b0, _M_finish = 0x7ffff6f5584d, _M_end_of_storage = 0x5509f0...
limit = -603988688

构造函数显然还没有完成执行。现在似乎还处于构建过程的早期阶段。我假设这四个操作都是false，然后是cols，所以下一步就是构造tableName。