CComPtr<istream> releasing problem</istream>

A Ms

Hi, I have used CComPtr class to declear two IStream type variable like below:

CComPtr<IStream> m_pStream;
CComPtr<IStream> m_pStream2;

and some where in my code I Create a stream on a file and let my m_pStream variable point at it like below:

::SHCreateStreamOnFileW(FileName,STGM_READWRITE | STGM_SHARE_DENY_WRITE,&pStream);

Now I want to do sth cause the first Stream variable "m_pStream" release the specified File, so I could create the stream on the same file and let my secound Stream variable m_pStream2 points at it like below:

::SHCreateStreamOnFileW(FileName,STGM_READWRITE | STGM_SHARE_DENY_WRITE,&pStream2);

because my Stream vars are defined with CComPtr class I coudn't use the Release method of my Stream variables. even I have tested nullifying the first Stream variable but it didn't solve my problem. What should I do?

KarstenK

use detach or different scope for the streams

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Stephen Hewitt

Amir_m wrote:

because my Stream vars are defined with CComPtr class I coudn't use the Release method of my Stream variables.

CComPtr has a Release[^] method. Use . ***NOT*** ->: pStream.Release();

Steve

A Ms

would you please explain it more I couldn't find any thing. a little code would be useful and there is no detach method

A Ms

of course I know But The Release Method of CComPtr Class is a private method and compiler does not let me to use it.

KarstenK

CComPtr::Detach() http://msdn.microsoft.com/en-us/library/w200fbea%28VS.80%29.aspx[^]

Press F1 for help or google it. Greetings from Germany

A Ms

for m_pStream->Detach(); I got the following Error:

Error 1 error C2039: 'Detach' : is not a member of 'ATL::_NoAddRefReleaseOnCComPtr<T>'

Even I taype cast my CComPtr to CComPtrBase but again there were only to Member functions which both were in private scope!:confused:

KingsGambit

May be you can try as follows:

void Foo()
{
{
CComPtr<IStream> m_pStream;
::SHCreateStreamOnFileW(...);
}

{
CComPtr<IStream> m_pStream2;
::SHCreateStreamOnFileW(...);
}
}

A Ms

My Problem is accessing the file because the Stream Created previously doesn't release the file I can't access the file with another stream (even nullifying that stream doesn't cause it to release the file)

KingsGambit

In the code segment in my previour post, m_pStream and m_pStream2 are in different scopes (between {}), so the streams will be closed automatically when the scope ends. So, both calls to SHCreateStreamOnFile(...) will be successfull.

KarstenK

Casting is absolutitly no solution for this problem!!! use different scope for both variables

Press F1 for help or google it. Greetings from Germany

Stephen Hewitt

Amir_m wrote:

of course I know But The Release Method of CComPtr Class is a private method and compiler does not let me to use it.

No, it's not private. The following compiles fine:

CComPtr<IStream> spStream;
spStream.Release();

Steve