Walter is right about transitive readonly - here's the alternative

[Steven Schveighoffer]

"Janice Caron" wrote
> On 9/14/07, Steven Schveighoffer <schveiguy at yahoo.com> wrote:
>> > And un-consting a mutex is probably the one place where it's
>> > absolutely safe to do so, no matter that other threads might be
>> > sharing it! Hot dang! That's brilliant!
>>
>> Hm.. The spec says that the result of casting away const and then 
>> modifying
>> the variable is "undefined."  I take this to mean that the compiler may 
>> do
>> some optimizations based on the fact that you have a const object, and 
>> then
>> your code might not behave as you think in some future version of D :(
>>
>> Although I think it has been suggested by Walter that casting away const 
>> is
>> acceptable if "you know what you're doing":
>
> Well, Walter's only mentioned one problem so far, which is that of an
> object which the compiler things is const being shared between
> multiple threads. Though strictly speaking overriding const is
> undefined, we do, in fact, know what would happen. Thread A would make
> a modification, and then thread B would see the change.

That sounds like a definition :)

To me, undefined means "I can't tell you what happens, my compiler is free 
to make assumtions that you cannot anticipate."  What you are describing is 
more like "not recommended".

-Steve