debugging COM free registration (c++)

Question

I've built a COM client application that uses two COM server dlls; I want this application to run without COM registration - ie: winsxs / .manifests

I get a (...almost expected...) "Class not registered" message when I try to create an instance of my COM object from my client application.

I've already succeeded that kind of configuration before but I cannot figure out why this one fail.

---

here are a few more details:

• the modules I have:
  • a MFC client that depends on 2 COM servers (dll1.dll and dll2.dll)
  • dll1.dll COM server depends on dll2.dll
  • dll2.dll has no COM dependency

the COM objects I have:

• in dll1.dll (.idl language)

-

[
    object,
    uuid(262D00FB-3B9F-4A76-98FC-3051FDCAF0A6),
    dual,
    nonextensible,
    helpstring("IDialogManager Interface"),
    pointer_default(unique)
]
interface IDialogManager : IDispatch{
};
[
        uuid(58562535-BCA5-4D04-BB92-78F90EDA201E),
        //...
]
dispinterface _IDialogManagerEvents
{
};
[
        uuid(D599D3F0-A4D1-44A7-87A9-16032CC613CA),
        //...
]
coclass DialogManager
{
        [default] interface IDialogManager;
        [default, source] dispinterface _IDialogManagerEvents;
};

-

• in dll2.dll

-

[
    object,
    uuid(2A183A2E-A620-4E00-B657-C9D2E59201D4),
    nonextensible,
    helpstring("ICadWizardsManager Interface"),
    pointer_default(unique)
]
interface ICadWizardsManager : IDispatch{
};
[
    object,
    uuid(FE97F3FB-8930-43BC-947D-64C90F45A071),
    nonextensible,
    helpstring("ICadWizard Interface"),
    pointer_default(unique)
]
interface ICadWizard : IDispatch{
};
[
    uuid(5365D4E6-ADFB-4429-9DEA-C44CC94AA3EF),
]
dispinterface _ICadWizardEvents
{
};
[
    uuid(CAC2D0BF-AD5B-4CC8-A04D-53AB23A0CDF4),
]
coclass CadWizard
{
    [default] interface ICadWizard;
    [default, source] dispinterface _ICadWizardEvents;
};
[
    uuid(3164FAC4-6F5F-4E4D-9B09-DC4115850D78),
]
dispinterface _ICadWizardsManagerEvents
{
};
[
    uuid(707CB6C8-311E-45EC-9DCB-50477F588BAF),
]
coclass CadWizardsManager
{
    [default] interface ICadWizardsManager;
    [default, source] dispinterface _ICadWizardsManagerEvents;
};

-

• the client call

-

IDialogManagerPtr dialogManager;
dialogManager.CreateInstance(CLSID_DialogManager); // <<< returns "Class not registered"

-

• the client.exe.2.manifest

-

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">

<assemblyIdentity name="client" version="1.0.0.0" type="win32" processorArchitecture="x86"/>
<file name="dll2.dll">
 <comClass
     clsid="{707CB6C8-311E-45EC-9DCB-50477F588BAF}"
     threadingModel="apartment">
 </comClass>
 <comClass
     clsid="{CAC2D0BF-AD5B-4CC8-A04D-53AB23A0CDF4}"
     threadingModel="apartment">
 </comClass>
</file>

<file name="dll1.dll">
 <comClass
     clsid="{D599D3F0-A4D1-44A7-87A9-16032CC613CA}"
     threadingModel="apartment">
 </comClass>
</file>

</assembly>

-

---

I have no error during sxs activation context generation: - no error in windows log (should means that my manifest syntax is correct) - no error detected by sxstrace (the log ends with "INFO: Activation Context generation succeeded." message and contains no error or sucpicious message; moreover, I see that my manifest is loaded correctly)

Any idea?

is there a way to debug sxs deeper that with sxstrace? getting the list of actually registered com or clr classes for instance???

Thank you by advance

Answer 1

There are usually - at least - two manifests involved when building the activation context for registration free COM.

There is the EXE manifest, that specifies its dependent assemblies, including the assembly containing the COM components, and there is the assembly manifest, describing the dll's, window classes, and COM objects in the assembly.

This Blog contains information about what the .2 means. Basically, when the system looks for a manifest, it looks for modulename.exe[.resid].manifest - In the case that resid is 1, it is omitted.

So, you are using MFC, which means DevStudio, which means that your project should already be configured to produce a RT_MANIFEST resource automatically with the c-runtime and common control 6 settings in it.

Visual Studio 2005 supports this syntax to merge dependentAssembly elements with your applications manifest without having to try and merge XML directly:

#pragma comment(linker, \
    "\"/manifestdependency:type='Win32' "\
    "name='client' "\
    "version='1.0.0.0' "\
    "processorArchitecture='*' "\
    "language='*'\"")

So, if you add that to a cpp or header in your .exe, and then save your client.exe.2.manifest as "client.manifest", you should be all systems go.

Answer 2

The simple explanation is that the .manifest file isn't being used. Which is highly likely in this scenario, your .exe almost certainly already contains a manifest, embedded as a resource. Very common for a MFC app to enable visual styles. And for code compiled by the VS2005 or 2008 compilers which embeds a manifest to find the runtime DLLs.

To verify this, use File + Open + File and select the compiled .exe file. Look for the RT_MANIFEST node. If Windows finds such an embedded manifest it isn't going to continue looking for a file-based one. You need to merge your regfree COM entries into the embedded one. I wish I could give you a good MSDN Library link but the docs about manifests suck serious rock.