Re: Freeing Memory for a BSTR*

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.language
Date:
Tue, 6 Oct 2009 09:10:57 -0400
Message-ID:
<#iFH0ZoRKHA.1280@TK2MSFTNGP04.phx.gbl>
Marcus de Leon wrote:

CComBSTR bstrName;

pCOMPobj->GetName(&bstrName); // See below

m_csName = bstrName;

SysFreeString(* bstrName);

bstrName = NULL;


You are corrupting memory by performing double destruction. CComBSTR
frees the BSTR it wraps (in the destructor or, as in this case, when a
different string or NULL is assigned to it). Drop SysFreeString call.

STDMETHODIMP GetName(BSTR* pbsName)
{
    CString csName = *pbsName;


What's the point of this line, when you reassign csName in the very next
line? In any case, since pbsName is an [out] parameter, you have to
assume that *pbsName is a random uninitialized garbage on input.

    csName = GetName();
    *pbsPatientName = csName.AllocSysString();


What's pbsPatientName? Is it in any way related to pbsName?
--
With best wishes,
    Igor Tandetnik

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