KB948986: VS 2005:error C2011: 'ICOMAdminCatalog' : 'struct' type redefinition

Question

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Link to Original Article from Microsoft Support

VS 2005:error C2011: 'ICOMAdminCatalog' : 'struct' type redefinition

Action

Add the following code to any .cpp source file of default generated ATL DLL project and compile:
   #include <comsvcs.h>
   #import "comadmin.dll" no_namespace named_guids

Result

You will get the following error:
{path to your project}\debug\comadmin.tlh(69) : error C2011: 'ICOMAdminCatalog' : 'struct' type redefinition
C:\Program Files (x86)\Microsoft Visual Studio 8\VC\PlatformSDK\include\comadmin.h(155) : see declaration of 'ICOMAdminCatalog'

Answer 1

Cause

Here the conflict is between the TLH file generated because of #import statement, and the comadmin.h header that is being #included through comsvcs.h.  The redefinition error is because all the enums and classes are generated as 'struct' in comadmin.tlh file, but comadmin.h declares them as classes.

Resolution

Remove 'no_namespace' from #import statement so that it generates the namespace.
Qualify all the references being made for classes and enums with the namespace identifier. For example:
COMAdmin::COMAdminAccessChecksApplicationLevel

Here 'COMAdmin' is the namespace identifier and COMAdminAccessChecksApplicationLevel is an enum value declared in the type library.

More Information

The same issue doesn't occur in VS 6.0 since comadmin.h declares classes and enums as structs. Projects that migrate from VS 6.0 to VS 2005 may face this kind of issue.

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