Re: Why do I need to overload =

From:

John Doe <mosfet@anonymous.org>

Newsgroups:

comp.lang.c++

Date:

Tue, 07 Oct 2008 17:39:23 +0200

Message-ID:

<48eb82ab$0$20859$426a34cc@news.free.fr>

I have finally replaced CString* in ThreadParam with LPCTSTR
and LPTSTR:

struct ThreadParam
    {
        ThreadParam(CProvisioning* a_pThis, LPCTSTR a_strConfig, LPTSTR
a_strXmlOut):
            pThis(a_pThis),
            pStrConfig( a_strConfig ),
            pStrOut( a_strXmlOut ) {}

        CProvisioning* pThis;
        LPCTSTR pStrConfig;
        LPTSTR pStrOut;
    };

BOOL CProvisioning::ProcessConfigXML(const CString& strConfig, CString&
strXmlOut)
{
    DWORD dwRet = 0;

    m_thrParam = ThreadParam(this, (LPCTSTR)strConfig,
(LPTSTR)(LPCTSTR)strXmlOut);
    m_hProvThread = CreateThread(
        NULL,
        0,
        &COmaProvisioning::ProvisioningThr,
        &m_thrParam,
        0, NULL);
...
}
  /*static*/
DWORD CProvisioning::ProvisioningThr(LPVOID pvarg)
{
     ThreadParam* pThrParam = static_cast<ThreadParam*>(pvarg);
     if (pThrParam) {
         COmaProvisioning* pThis = pThrParam->pThis;
         if (pThis)
         {
             return pThis->ProvisioningThr(
                 CString(pThis->m_thrParam.pStrConfig),
                 CString(pThis->m_thrParam.pStrOut);
         }
            }

     return -1;
}

but obviously now my reference string passed in ProcessConfigXML is not
modified since I pass a temporary reference
CString(pThis->m_thrParam.pStrOut.

Finally I am going to use old plain C interface LPCTSTR and LPSTR
because like this it works ...
I don 't understand why I try complicated things in C++

Hum I thinl I have understood why it couldn't work:

LPTSTR szXmlIn = NULL;
CString strXmlFmtOut;

m_OmaProv.ProcessConfigXML(szXmlIn, strXmlFmtOut);

When I call ProcessConfigXML , first argument is a C char array =>
CString objects are create temporarly then I save a pointer to ths
temporary object :

BOOL CProvisioning::ProcessConfigXML(const CString& strConfig, CString&
strXmlOut)
{
m_thrParam = ThreadParam(this, &strConfig, &strXmlOut);
....
}
So I suppose address of &strConfig is temporary ...

Am I wrong ?