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title: "defaultvtable | Microsoft Docs"
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---
# defaultvtable
Defines an interface as the default vtable interface for a COM object.  
  
## Syntax  
  
```  
  
      [ defaultvtable(  
   interface  
) ]  
```  
  
#### Parameters  
 `interface`  
 The designated interface that you want to have the default vtable for the COM object.  
  
## Remarks  
 The **defaultvtable** C++ attribute has the same functionality as the [defaultvtable](http://msdn.microsoft.com/library/windows/desktop/aa366795) MIDL attribute.  
  
## Example  
 The following code shows attributes on a class that use **defaultvtable** to specify a default interface:  
  
```  
// cpp_attr_ref_defaultvtable.cpp  
// compile with: /LD  
#include <unknwn.h>  
[module(name="MyLib")];  
  
[object, uuid("00000000-0000-0000-0000-000000000001")]  
__interface IMyI1 {  
   HRESULT x();  
};  
  
[object, uuid("00000000-0000-0000-0000-000000000002")]  
__interface IMyI2 {  
   HRESULT x();  
};  
  
[object, uuid("00000000-0000-0000-0000-000000000003")]  
__interface IMyI3 {  
   HRESULT x();  
};  
  
[coclass, source(IMyI3, IMyI1), default(IMyI3, IMyI2), defaultvtable(IMyI1),  
uuid("00000000-0000-0000-0000-000000000004")]  
class CMyC3 : public IMyI3 {};  
```  
  
## Requirements  
  
### Attribute Context  
  
|||  
|-|-|  
|**Applies to**|**class**, `struct`|  
|**Repeatable**|No|  
|**Required attributes**|**coclass**|  
|**Invalid attributes**|None|  
  
 For more information, see [Attribute Contexts](../windows/attribute-contexts.md).  
  
## See Also  
 [IDL Attributes](../windows/idl-attributes.md)   
 [Class Attributes](../windows/class-attributes.md)