Re: Need help with COM dll registration at runtime

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.language
Date:
Mon, 12 Mar 2007 08:44:16 -0400
Message-ID:
<eGXomQKZHHA.2436@TK2MSFTNGP06.phx.gbl>
"Suman" <skarpio@gmail.com> wrote in message
news:1173695708.494916.223060@8g2000cwh.googlegroups.com

I have only recently started getting my feet wet with COM and have run
into a couple of issues.
I'd appreciate any help that you provide. My reference will be one
article found at:
http://www.codeproject.com/com/com_in_c1.asp


Realize that the article describes the hardest, most verbose and
inconvenient way of doing COM. It's great as a studying material, to
understand what's going on under the hood. But for writing everyday
code, there are better ways.

(I do know about CLSIDFromString() but somehow
just couldn't get past
converting char [] to OLESTR


MultiByteToWideChar. OLESTR is a typedef for WCHAR*, aka wchar_t* .

Note, I call a function to do register this dll, and uptio this,
things work fine. Actually, the CustomRegister() function
is also taken from the codeproject tutorial. However,
CoGetClassObject() fails saying:
"ClassFactory cannot supply requested class".


Check that the DLL is indeed registered successfully. Check in the
registry under

HKEY_CLASSES_ROOT\CLSID\{Your CLSID}

In particular, there should be InprocServer32 subkey under this key,
whose default value contains full path to the DLL.

void GetCLSIDFromFile(const char *path, char *out)
{
   if (out) {
       //*out = 0;
       FILE *fp = fopen(path, "r");
       if (fp) {
           fscanf(fp, "CLSID=%s%*", out);


%* is not a valid format specifier. Does this function succeed? Do you
get expected CLSID when this function returns?

   CustomRegister(ri);


What does CustomRegister do? It is unusual for the client to register
the COM object it's about to use. Normally, the COM object is registered
at installation time.
--
With best wishes,
    Igor Tandetnik

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