Pointers in ASP

[MeAndI]

Hi to all,

I've integrate a custom ActiveX (builded in C++) in my ASP pages, but now I
have a question/problem.
I have a function which uses the pointers as parameters.
When I call this function in my ASP page I have this error (Data type
missmatch..)
e.g.
dim param1
dim param2
param1 = ""
param2 = ""
retval = myActiveX.myFunction (param1, param2)

myFunction is declared as follow:
long CmyActiveXCtrl::myFunction(BSTR FAR* param1, BSTR FAR* param2)

It is possible to call this function without making changes to the ActiveX
source code?

Please help
Thanks

[Mark Schupp]

I don't think so.

I haven't done may C++ com objects that return strings but I am pretty sure
that you have to return the value by using pointers to VARIANT. That's what
the methods I created used do and they work.

Here are the key parts of a working function that returns a single string
( I've removed some code that doesn't affect returning the string):

STDMETHODIMP CHTTPDloader::ASyncGet(BSTR strTargetURL, BSTR strDestDir, long
nOptions, VARIANT* strDownloadID)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState())

USES_CONVERSION;

ASSERT( strDownloadID != NULL );
if( strDownloadID == NULL )
{
return( E_POINTER );
}

try
{

CString strURL;
CString strDestination;
COleVariant vtOut;

strURL = OLE2T( strTargetURL );
strDestination = OLE2T( strDestDir );

//clear any existing value
vtOut.Attach( *strDownloadID );
vtOut.Clear();

vtOut.Detach();
strDownloadID->vt = VT_BSTR;
strDownloadID->bstrVal = (DoAsyncGet( strURL, strDestination,
nOptions )).AllocSysString();

}
catch(...)
{
return E_FAIL;
}

return S_OK;
}

--
Mark Schupp
Head of Development
Integrity eLearning
www.ielearning.com
"MeAndI" <se******@libero.it> wrote in message
news:P1**********************@twister2.libero.it.. .

Hi to all,

I've integrate a custom ActiveX (builded in C++) in my ASP pages, but now I have a question/problem.
I have a function which uses the pointers as parameters.
When I call this function in my ASP page I have this error (Data type
missmatch..)
e.g.
dim param1
dim param2
param1 = ""
param2 = ""
retval = myActiveX.myFunction (param1, param2)

myFunction is declared as follow:
long CmyActiveXCtrl::myFunction(BSTR FAR* param1, BSTR FAR* param2)

It is possible to call this function without making changes to the ActiveX
source code?

Please help
Thanks

[MeAndI]

OK Mark.
Now I understand, thanks

The problem happens because the pointer type is BSTR instead of VARIANT.
But now I have another question for you:

My ASP code is:

<%
objectTest = Server.CreateObject("myobject.progID")
dim retval
retval = objectTest.eFunction()
%>

The object creation is done correctly, but when I call one function that
doesn't need params I have the following error:
0x8000FFFF (Catastrophic failure)

Do you have thoughts?
"Mark Schupp" <ms*****@ielearning.com> ha scritto nel messaggio
news:eo*************@tk2msftngp13.phx.gbl...

I don't think so.

I haven't done may C++ com objects that return strings but I am pretty sure that you have to return the value by using pointers to VARIANT. That's what the methods I created used do and they work.

Here are the key parts of a working function that returns a single string
( I've removed some code that doesn't affect returning the string):

STDMETHODIMP CHTTPDloader::ASyncGet(BSTR strTargetURL, BSTR strDestDir, long nOptions, VARIANT* strDownloadID)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState())

USES_CONVERSION;

ASSERT( strDownloadID != NULL );
if( strDownloadID == NULL )
{
return( E_POINTER );
}

try
{

CString strURL;
CString strDestination;
COleVariant vtOut;

strURL = OLE2T( strTargetURL );
strDestination = OLE2T( strDestDir );

//clear any existing value
vtOut.Attach( *strDownloadID );
vtOut.Clear();

vtOut.Detach();
strDownloadID->vt = VT_BSTR;
strDownloadID->bstrVal = (DoAsyncGet( strURL, strDestination,
nOptions )).AllocSysString();

}
catch(...)
{
return E_FAIL;
}

return S_OK;
}

--
Mark Schupp
Head of Development
Integrity eLearning
www.ielearning.com
"MeAndI" <se******@libero.it> wrote in message
news:P1**********************@twister2.libero.it.. .

Hi to all,

I've integrate a custom ActiveX (builded in C++) in my ASP pages, but now

I

have a question/problem.
I have a function which uses the pointers as parameters.
When I call this function in my ASP page I have this error (Data type
missmatch..)
e.g.
dim param1
dim param2
param1 = ""
param2 = ""
retval = myActiveX.myFunction (param1, param2)

myFunction is declared as follow:
long CmyActiveXCtrl::myFunction(BSTR FAR* param1, BSTR FAR* param2)

It is possible to call this function without making changes to the

ActiveX source code?

Please help
Thanks

[Mark Schupp]

I would remove all code from the function except that needed to return the
value. Make sure that there is no error with the empty function. Then
gradually add code back in until the error returns. That will tell what is
causing it.

--
Mark Schupp
Head of Development
Integrity eLearning
www.ielearning.com
"MeAndI" <se******@libero.it> wrote in message
news:W4**********************@twister2.libero.it.. .

OK Mark.
Now I understand, thanks

The problem happens because the pointer type is BSTR instead of VARIANT.
But now I have another question for you:

My ASP code is:

<%
objectTest = Server.CreateObject("myobject.progID")
dim retval
retval = objectTest.eFunction()
%>

The object creation is done correctly, but when I call one function that
doesn't need params I have the following error:
0x8000FFFF (Catastrophic failure)

Do you have thoughts?
"Mark Schupp" <ms*****@ielearning.com> ha scritto nel messaggio
news:eo*************@tk2msftngp13.phx.gbl...

I don't think so.

I haven't done may C++ com objects that return strings but I am pretty

sure

that you have to return the value by using pointers to VARIANT. That's

what

the methods I created used do and they work.

Here are the key parts of a working function that returns a single string

( I've removed some code that doesn't affect returning the string):

STDMETHODIMP CHTTPDloader::ASyncGet(BSTR strTargetURL, BSTR strDestDir,

long

nOptions, VARIANT* strDownloadID)
{
AFX_MANAGE_STATE(AfxGetStaticModuleState())

USES_CONVERSION;

ASSERT( strDownloadID != NULL );
if( strDownloadID == NULL )
{
return( E_POINTER );
}

try
{

CString strURL;
CString strDestination;
COleVariant vtOut;

strURL = OLE2T( strTargetURL );
strDestination = OLE2T( strDestDir );

//clear any existing value
vtOut.Attach( *strDownloadID );
vtOut.Clear();

vtOut.Detach();
strDownloadID->vt = VT_BSTR;
strDownloadID->bstrVal = (DoAsyncGet( strURL, strDestination,
nOptions )).AllocSysString();

}
catch(...)
{
return E_FAIL;
}

return S_OK;
}

--
Mark Schupp
Head of Development
Integrity eLearning
www.ielearning.com
"MeAndI" <se******@libero.it> wrote in message
news:P1**********************@twister2.libero.it.. .

Hi to all,

I've integrate a custom ActiveX (builded in C++) in my ASP pages, but

now

I

have a question/problem.
I have a function which uses the pointers as parameters.
When I call this function in my ASP page I have this error (Data type
missmatch..)
e.g.
dim param1
dim param2
param1 = ""
param2 = ""
retval = myActiveX.myFunction (param1, param2)

myFunction is declared as follow:
long CmyActiveXCtrl::myFunction(BSTR FAR* param1, BSTR FAR* param2)

It is possible to call this function without making changes to the

ActiveX source code?

Please help
Thanks