first_is

Article
01/03/2018

The latest version of this topic can be found at first_is.

Specifies the index of the first array element to be transmitted.

Syntax

  
      [ first_is(  
   "expression"  
) ]

Parameters

expression
One or more C-language expressions. Empty argument slots are allowed.

Remarks

The first_is C++ attribute has the same functionality as the first_is MIDL attribute.

Example

The following code shows various ways to specify a section in an array:

// cpp_attr_ref_first_is.cpp  
// compile with: /LD  
#include "windows.h"  
#include "unknwn.h"  
  
[module(name="MyLib")];  
  
[object, uuid(11111111-1111-1111-1111-111111111111)]  
__interface b   
{  
   [id(0), propget, bindable, displaybind, defaultbind,   
requestedit] HRESULT get_I([out, retval]long *i);  
   HRESULT Proc1([in] short First, [in] short Last,   
[first_is(First), last_is(Last), size_is(Last-First)] char Arr1[]);   
   HRESULT Proc2([in] short First, [in] short Last,   
[last_is(First), size_is(Last)] char Arr2[]);  
};

Requirements

Attribute Context

Applies to	Field in `struct` or union, interface parameter, interface method
Repeatable	No
Required attributes	None
Invalid attributes	None

For more information, see Attribute Contexts.

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