PRB: Operator New Can't Be Called for CONST or VOLATILE Types (120878)

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 *;
   }