Re: CString help

On Mon, 25 Jun 2007 00:26:54 -0700, "Mihai N." <nmihai_year_2000@xxxxxxxxx>
wrote:

The following will be fine:

string s;
s.resize(n);
memset(&s[0], 0, n);

One of the benefits to requiring s[0] to return a real reference (which is
what disallows COW) is that &s[0] returns a real pointer.

From wat I know works in all current implementations, but still not
*guaranteed* by the standard in any way.

This is going 'round in circles. :) You've restated what I said at the
beginning:

<q>
Practically speaking, you can do this:

const int N = 100;
std::string s;
s.resize(N);
int len = WindowsAPI(&s[0], N);
s.resize(len);

Though not guaranteed, I don't know any implementation where this won't
work. (I'd really like the non-contiguity, reference-counted, etc options
to just go away. People who need those things can't do without them, and
the possibility they exist complicates things for everyone else.)
</q>

I later posted a link to this proposal, whose adoption guarantees this
currently univerally supported behavior:

530. Must elements of a string be contiguous?
http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#530

In my previous message, I was responding to your comment about "After
reading your open-std.org link..." to give you an example of the sort of
things it makes kosher. I could have posted my earlier example instead,
because it's the same thing. Besides completing the circle, your latest
reply is a great example of what I meant by, "the possibility they exist
complicates things for everyone else." Even after I started by saying it's
non-standard, though TTBOMK universally supported, then posted a link to a
document that indicates it will become standardized, you came back with,
"it's not standard". Like I said, going 'round in circles. :)

Bottom line: Unless you want to reserve the possibility of replacing
std::string with flex_string or whatever, you should feel free to go ahead
and use the technique I presented, which comes in really handy when dealing
with Windows APIs. You should even feel good about it. :)

--
Doug Harrison
Visual C++ MVP
.

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