On 9/23/2011 6:55 PM, Jonathan M Davis wrote:
True, but it doesn't just happen. You have to choose to make a variable
mutable.
Which you *must* do for logical const. And, of course, anything beyond the first
level is not const at all, and there's NO WAY to say it is const.
_Some_ effort must be put in to circumvent const. Until you do that,
const protects it from be changed.
There's no way to detect who or what is changing it.
By no means am I claiming that C++'s const is without flaws. I'm just claiming
that it's not worthless, and you seem to be claiming that it's worthless.
I think it is worthless because:
1. a number of C++ programmers I've talked to who relied on being able to change
const objects and insisted that was a feature.
2. the pervasive misconceptions about what C++ const guarantees and what it
doesn't, even among C++ committee members.
3. the complete uselessness C++ const has for multithreaded programming.
4. the pervasiveness of the Double Checked Locking Bug, which is one of the
consequences of (3).
5. it's head-const only. Anything beyond one level of indirection is completely
const-free. Only trivial data structures are one level.
