range (C++)

發行項
01/03/2018

The latest version of this topic can be found at range (C++).

Specifies a range of allowable values for arguments or fields whose values are set at run time.

Syntax

  
      [ range(  
   low,   
   high  
) ]

Parameters

low
The low range value.

high
The high range value.

Remarks

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

Example

// cpp_attr_ref_range.cpp  
// compile with: /LD  
#include <unknwn.h>  
[module(name="MyLib")];  
  
[object, uuid("9E66A290-4365-11D2-A997-00C04FA37DDB")]  
__interface ICustom {  
   HRESULT Custom([in] long l, [out, retval] long *pLong);  
   HRESULT length_is1([in, range(0, 999)] long f, [in, length_is(f)] char array[10]);  
   HRESULT length_is2([in, range(-99, -1)] long f, [in, length_is("f"), size_is(10)] char *array);  
};

Requirements

Attribute Context

Applies to	Interface method, interface parameter
Repeatable	No
Required attributes	None
Invalid attributes	None

For more information about the attribute contexts, see Attribute Contexts.

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