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Memory Leak in _connectionPtr.open??

Posted on 2004-08-31
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Last Modified: 2008-02-07
I am running a simple ADO test.   I am using VC++ 6 on Windows XP.  When evaluating the code with Rational Purify I get a memeory leak.   What am I doing wrong?

*****SAMPLE CODE:::

#include "StdAfx.h"
#import "c:\Program Files\Common Files\System\ADO\msado15.dll" \
              rename("EOF", "EndOfFile")


int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
      ::CoInitialize(NULL);

      ADODB::_ConnectionPtr      _cnn;

      try      
      {
            HRESULT hr;
            hr    = _cnn.CreateInstance( __uuidof(ADODB::Connection ) );
            _cnn->Open("DSN=ZIPS", L"",L"", ADODB::adModeUnknown);
      }catch (...)
      {
      }

      _cnn->Close();
      _cnn.Release();
      _cnn=NULL;
      ::CoUninitialize();
      return 0;
}

*******OUTPUT FROM PURIFY:

[W] MLK: Memory leak of 4096 bytes from 1 block allocated in ADODB::Connection15::Open(_bstr_t,_bstr_t,_bstr_t,long) [UnitTests.exe]
        Distribution of leaked blocks
        Allocation location
            VirtualAlloc   [KERNEL32.dll]
            ADODB::Connection15::Open(_bstr_t,_bstr_t,_bstr_t,long) [msado15.tli:367]
                inline HRESULT Connection15::Open ( _bstr_t ConnectionString, _bstr_t UserID, _bstr_t Password, long Options ) {
             =>     HRESULT _hr = raw_Open(ConnectionString, UserID, Password, Options);
                    if (FAILED(_hr)) _com_issue_errorex(_hr, this, __uuidof(this));
                    return _hr;
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Question by:nicoleheritage
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Author Comment

by:nicoleheritage
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I am using an ODBC connection to mircosoft Access for testing
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jacobhoover earned 500 total points
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Everything looks fine.... I personallly moved away from ADO and I use pure ODBC API.  I found a nifty little library from Gehtsoft (GSODBC) that wrapped up most all of the functionality I needed and best of all I was able to eliminate COM from my project.

It would also be interesting to know if Rational wasn't making a mistake with tracking the VirtualAlloc.  One could do a test and run your app 50 times and see if it truely is leaking the memory or if Purify wasn't mistaken.

Just my 2 cents...
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Author Comment

by:nicoleheritage
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I agree with your 2 cents and will be heading in that directions.

Thanks,

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Expert Comment

by:jacobhoover
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If you need a copy of the ODBC library, I would be more that happy to supply you one...  I think I origionally got mine off off codeguru.earthweb.com but I remember it taking some time for me to find the link.
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Expert Comment

by:jacobhoover
Comment Utility
Sure, no more than do I say that than do I google it and get a couple hits on it.

http://www.codeguru.com/Cpp/data/mfc_database/odbc/article.php/c4337/
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