From: williamkempf_at_[hidden]
Date: 2001-10-08 09:27:01
--- In boost_at_y..., Howard Hinnant <hinnant_at_t...> wrote:
> On Saturday, October 6, 2001, at 08:17 AM, Kevlin Henney wrote:
>
> >> Maybe you ought to write up a defect report. It will be easier
for
> >> the LWG
> >> to understand the issue if you boil it down to a very simple
piece of
> >> code
> >> that you want to know is or isn't conforming.
> >>
> >> Let's see. Something like this:
> >>
> >> #include <stdexcept>
> >>
> >> class lock_error : public std::runtime_error
> >> {
> >> public:
> >> lock_error() : std::runtime_error("thread lock error") { }
> >> };
> >>
> >> Is this conforming code? Note the lack of #include <string>,
> >> that std::runtime_error() takes a const string& argument, and
> >> there is no constructor taking a const char*.
> >>
> >> Post it on comp.std.c++ with a subject that begins "Defect
Report:"
> >
> > I believe that this issue (between <stdexcept> and <string>) is a
known
> > problem, although I don't know if it's yet a DR. It has at least
been
> > mentioned in passing by myself, Howard Hinnant and a couple of
others at
> > one or other of the ISO meetings in the last year (and the cyclic
> > dependency problem was also the basis for a general solution I
wrote up
> > in http://www.cuj.com/experts/1911/henney.htm).
>
> Martin Sebor has repeatedly tried to get a dr issue going in this
> general area (not specifically with <string> and <stdexcept>) and
> failed. This issue came up in the hs_conformance reflector prior
to the
> CUJ Vendor Review article. In that case it did deal specifically
with
> <string> and <stdexcept>.
>
> I believe the standard should say more about this issue, but I to
not
> have the standard-eze in hand. Several people have proposed rules,
and
> I believe that at least an informal consensus may be forming. My
> personal opinion, which has been influenced by similar words
already
> spoken by noted experts, is that the standard should say something
like:
>
> > If you explicitly use a standard defined name, then you must
explicitly
> > include the associated header. Otherwise you do not have to
include
> > the header, even if you are implicitly referring to said object.
>
> Of course the above "rule" would have to be encoded in standard-eze
so
> that only high priests are capable of interpreting its true
meaning. ;-)
>
> Under this rule, Beman's example would be conforming because it
only
> implicitly refers to std::string, not explicitly. Thus #include
> <string> is not necessary. If the example were changed to:
>
> lock_error() : std::runtime_error(std::string("thread lock
> error")) { }
>
> then #include <string> becomes necessary.
>
> Just my .02.
I'm glad others feel the same as I. Do I need to try and propose yet
another defect on this subject or is there any progress occuring
within the comittee on at least discussing this issue?
Bill Kempf