Q120878: PRB: Operator New Can’t Be Called for CONST or VOLATILE Types

Article: Q120878
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,1.51,1.52,2.0,2.1,4.0,5.0
Operating System(s): 
Keyword(s): kberrmsg kbLangCPP kbVC
Last Modified: 11-FEB-2002

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The information in this article applies to:

- Microsoft Visual C++, versions 1.0, 1.5, 1.51, 1.52, 2.0, 2.1, 4.0 
- Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
- Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
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SYMPTOMS
========

When trying to allocate memory from the heap on const or volatile types, you may
see this error:

  error C2468: 'new' : cannot allocate 'const'/'volatile' objects
  (type is 'const int ')

CAUSE
=====

This behavior is by design. For any type T, the type-specifier cannot contain
const T or volatile T. For example, the following type-specifiers won't work:

  new const int;        // Returns 'const int *'
  new volatile int;     // Returns 'volatile int *'
  new int * const;      // Returns 'int * const *'
  new int * volatile;   // Returns 'int * volatile *'

RESOLUTION
==========

The following type-specifiers will work:

  new int const *;      // Returns 'int const **' (or 'const int**')
  new int volatile *;   // Returns 'int volatile **'
                        // (or 'volatile int**')

MORE INFORMATION
================

For more information, please see the description on 'new Operator' in the C++
Language Reference that comes with Microsoft C/C++ version 7.0 and Microsoft
Visual C++ version 1.0 for Windows or Windows NT.

Sample Code
-----------

     /* Compile options needed: /c /W3
     */ 

     void main(void)
     {
     // illegal

       // Would return a 'const int *'
            const int* i = new const int;

       // Would return a 'volatile int *'
            volatile int* j = new volatile int;

       // Would return a 'int * const *'
            int* const* k = new int * const;

       // Would return a 'int * volatile *'
            int* volatile* l = new int * volatile;

     // legal

         // pointer to const pointer to int
             int const* *m = new int const *;

             int volatile* *n = new int volatile *;
     }

Additional query words: errmsg 8.00 8.00c 9.00 9.10

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Keywords          : kberrmsg kbLangCPP kbVC 
Technology        : kbVCsearch kbVC400 kbAudDeveloper kbvc150 kbvc100 kbVC500 kbVC151 kbVC200 kbVC210 kbVC32bitSearch kbVC152 kbVC500Search
Version           : :1.0,1.5,1.51,1.52,2.0,2.1,4.0,5.0
Issue type        : kbprb

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