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first_is

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

[ 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.

See Also

Reference

last_is

max_is

length_is

size_is

Concepts

Visual C++ Samples

Other Resources

IDL Attributes

Typedef, Enum, Union, and Struct Attributes

Parameter Attributes