Re: cstring_view

From: Peter Dimov (pdimov_at_[hidden])
Date: 2022-05-13 22:19:33

Marshall Clow wrote:
> On May 13, 2022, at 12:29 PM, Rainer Deyke via Boost
> <boost_at_[hidden]> wrote:
> >
> > On 13.05.22 20:39, Marshall Clow via Boost wrote:
> >> On May 13, 2022, at 11:18 AM, Peter Dimov via Boost
> <boost_at_[hidden]> wrote:
> >>> In what scenarios will it not give you a null-terminated string?
> >> 	char arr[6] = “hello";
> >> 	cstring_view csv(arr);
> >> 	assert(strlen(csv.data())) == 5);
> >>         arr[5] = ‘!’;
> >> 	assert(strlen(csv.data())) == 5);  // boom — Marshall PS. It
> >> promises to give you a null-terminated string, but has no way to actually
> guarantee that.
> >
> > That's an issue with views in general, not just cstring_view.
> >
> >  std::string s = "hello";
> >  string_view sv = s;
> >  assert(sv.size() == 5);
> >  s += "!";
> >  assert(sv.size() == 5); // boom
> 
> I don’t see the problem here (and when I run the code I get no error - after
> adding the missing ’std::').
> 
> No assertion failure; no undefined behavior (unlike the cstring_view example)

Only because "hello!" fits into the small buffer, I suspect. If `s` reallocates,
`sv` would be left dangling.