so what exactly is const supposed to mean?

Bruno Medeiros brunodomedeirosATgmail at
Tue Jul 4 03:32:58 PDT 2006

Sean Kelly wrote:
> Bruno Medeiros wrote:
>> Sean Kelly wrote:
>>>  > and doesn't D already have a const keyword?
>>> D has const as a storage attribute, which is a bit different from the 
>>> above.  D's const may only apply to concrete data types, and implies 
>>> that the data will never be modified for the duration of the program. 
>>> This allows the compiler to place such data in ROM and to perform 
>>> some optimizations that would otherwise not be possible.  But this is 
>>> quite limited in that it may only be applied to data that can be 
>>> evaluated at compile-time.
>> There is a slight difference from D's const and a const that places 
>> the data in ROM as you cannot get the address of a D const var (it's 
>> not an lvalue).
> Ever tried taking the address of a const string?  That you can't take 
> the address of other const types is simply a result of optimization.

I tried it now, and the const string also can't be taken an address from:

   const char[] str = "ABC";

   void func()
     *(&str) = "123"; // : "ABC" is not an lvalue

Bruno Medeiros - CS/E student

More information about the Digitalmars-d-learn mailing list