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Re: libstdc++/16612, empty basic_strings can't live in shared memory
On Wed, Aug 04, 2004 at 09:48:21AM -0400, Phil Edwards wrote:
> I can't recall ever hearing a good explanation for this requirement.
> If somebody can provide one, I'll change my stance, otherwise I'll go out
> on a limb and suggest we just ignore it. (And document that we do so.)
> If we do, I will wager $5000ZWD that no real-world programmer will notice
> the omission, nor care.
The idea is probably that given
char const* s1 = "foobar";
std::string s2 = s1;
Then for any 'n' for which s1[n] returns a defined value,
s2[n] returns the same value.
However, since after
char const* p1 = &s2[s2.length() - 1];
char const* p2 = &s2[s2.length()];
still (p1 + 1) != p2, and *(p1 + 1) has undefined behaviour - I think that
indeed this is only confusing.
Worse - if the above causes *p2 to be defined, then what if
we do char* p3 = &s2[s2.length()]; *p3 = 0; ? Core dump
because we try to write to a read-only section?
I agree that this whole extension is very unlogical; one
can't discourage a programmer enough to use it.
Carlo Wood <email@example.com>