---
title: "custom (C++) | Microsoft Docs"
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ms.date: "11/04/2016"
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---
# custom (C++)
Defines metadata for an object in the type library.  
  
## Syntax  
  
```  
  
      [ custom(  
   uuid,   
   value  
) ];  
```  
  
#### Parameters  
 *uuid*  
 A unique ID.  
  
 *value*  
 A value that can be put into a variant.  
  
## Remarks  
 The **custom** C++ attribute will cause information to be placed into the type library. You will need a tool that reads the custom value from type library.  
  
 The **custom** attribute has the same functionality as the [custom](http://msdn.microsoft.com/library/windows/desktop/aa366766) MIDL attribute.  
  
## Requirements  
  
### Attribute Context  
  
|||  
|-|-|  
|**Applies to**|Non-COM `interface`, **class**, `enum`s, `idl_module` methods, interface members, interface parameters, `typedef`s, **union**s, `struct`s|  
|**Repeatable**|Yes|  
|**Required attributes**|**coclass** (when used on class)|  
|**Invalid attributes**|None|  
  
 For more information about the attribute contexts, see [Attribute Contexts](../windows/attribute-contexts.md).  
  
## See Also  
 [IDL Attributes](../windows/idl-attributes.md)   
 [Stand-Alone Attributes](../windows/stand-alone-attributes.md)   
 [Typedef, Enum, Union, and Struct Attributes](../windows/typedef-enum-union-and-struct-attributes.md)   
 [Parameter Attributes](../windows/parameter-attributes.md)   
 [Method Attributes](../windows/method-attributes.md)   
 [Class Attributes](../windows/class-attributes.md)   
 [Interface Attributes](../windows/interface-attributes.md)