CocreateInstance fails

Shailesh Ha

Hi, Problem is that A call to CocreateInstance fails ....hence the requested interface pointer shown is NULL ...hrStatus = CoCreateInstance( clsControl, NULL, CLSCTX_INPROC_SERVER, IID_Control, reinterpret_cast(&m_pControl) ); ABOVE the IID_Control is showing as NULL... Any solutions , Kindly let me know regards Shailesh

prasad_som

Shailesh Halankar wrote:

ABOVE the IID_Control is showing as NULL...

I think, you wants to say, m_pControl is NULL. Can you show complete code ? Have you used ::CoInitialize(NULL) before calling CoCreateInstance?

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Stephen Hewitt

Your code is hard to read. What is the HRESULT returned? Try entering "hr, hr" in your debugger watch window, assuming the variable containing the HRESULT returned from CoCreateInstance is named "hr". If it was named "MyHr" you'd use the following string: "MyHr, hr".

Steve

Shailesh Ha

Hello ur right m_pControl is NULL ..hence error.. I can giv u some more of the code ... HRESULT hrStatus = CLSIDFromProgID( TEXT("What ever prog ID"), &clsControl ); if( SUCCEEDED(hrStatus) ) { // // Create the object and initialize it. // hrStatus = CoCreateInstance( clsControl, NULL, CLSCTX_INPROC_SERVER, IID_IControl, reinterpret_cast(&m_pControl) ); if( SUCCEEDED(hrStatus) ) { // some code } }

prasad_som

Shailesh Halankar wrote:

HRESULT hrStatus = CLSIDFromProgID( TEXT("What ever prog ID"), &clsControl ); if( SUCCEEDED(hrStatus) )

I think you are getting class id here. Call, ::Coinitialize(NULL) before it.

Shailesh Halankar wrote:

hrStatus = CoCreateInstance( clsControl, NULL, CLSCTX_INPROC_SERVER, IID_IControl, reinterpret_cast(&m_pControl) );

What is value of hrstatus here?

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Shailesh Ha

Hi Prasad I cant use coinitialize function ..gives linker error..i think its coz its not a VC++ apllication that i m working on . Its a Embeded VC++ application that i m working on. regards Shailesh

prasad_som

Shailesh Halankar wrote:

..gives linker error

You need to link Ole232.lib.

Shailesh Halankar wrote:

i think its coz its not a VC++ apllication that i m working on . Its a Embeded VC++ application that i m working on.

Doesn't matter. BTW, you haven't answered my second question , about value of hresult.

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Shailesh Ha

my code ..is somewat like this HRESULT hrStatus = CLSIDFromProgID( TEXT("some"), &clsControl ); if( SUCCEEDED(hrStatus) ) { // // Create the object and initialize it. // hrStatus = CoCreateInstance( clsControl, NULL, CLSCTX_INPROC_SERVER, IID_IControl, reinterpret_cast(&m_pControl) ); if( SUCCEEDED(hrStatus) ) { //some code } } regards Shailesh

Stephen Hewitt

Put a break point directly after the CoCreateInstance call you're having problems with. When the break point is hit add the following to the watch window: "hrStatus, hr". If all goes well your debugger will tell you what the problem is.

Steve

prasad_som

Hi Shailesh, What happens to your problem ? Its always good practice to reply, whether you problem has been solved or not. It helps other to add this problem to their knowledege. And reply further if not solved.

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