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From "Eric Lemings" <Eric.Lemi...@roguewave.com>
Subject RE: [STDCXX-550] Please peer review this change.
Date Mon, 02 Jun 2008 22:38:38 GMT
 

> -----Original Message-----
> From: Martin Sebor [mailto:msebor@gmail.com] On Behalf Of Martin Sebor
> Sent: Monday, June 02, 2008 4:21 PM
> To: dev@stdcxx.apache.org
> Subject: Re: [STDCXX-550] Please peer review this change.
> 
> Eric Lemings wrote:
> >  
> > 
> >> -----Original Message-----
> >> From: Martin Sebor [mailto:sebor@roguewave.com] 
> >> Sent: Monday, June 02, 2008 2:44 PM
> >> To: dev@stdcxx.apache.org
> >> Subject: Re: [STDCXX-550] Please peer review this change.
> >>
> >> Eric Lemings wrote:
> >>>  
> >>> Would like to get another set of eyes on this before I submit.
> >>>
> >>> $ svn diff include/deque
> >>> Index: include/deque
> >>> 
> ===================================================================
> >>> --- include/deque       (revision 662487)
> >>> +++ include/deque       (working copy)
> >>> @@ -749,7 +749,7 @@
> >>>      void _C_insert (const iterator &__it,
> >>>                      _IntType __n, _IntType __x, int) {
> >>>          // see 23.1.1, p9 and DR 438
> >>> -        _C_insert_n (__it, __n, __x);
> >>> +        _C_insert_n (__it, __n, const_reference (__x));
> >> I suspect this is not correct. Suppose the type of __x is
> >> a 4 byte int and const_reference is an 8 byte long. The cast
> >> will make _C_insert_n() to read 4 bytes past the end of __x.
> >> A better fix might be to cast __x to value_type, as long as
> >> doing so doesn't violate [sequence.reqmts].
> > 
> > Yep.  Good call.  Will change to value_type() cast.
> 
> Do read DR 438 before applying the cast. There are some obscure
> corner cases here, e.g., IntType being a user-defined "integer-
> like" type. I don't know if we support this case now, or if we
> do, if it's being tested, but suffice it to say that there are
> subtle differences between direct-initialization either via
> a function-style cast or static_cast, or copy-initialization
> (passing arguments to functions).

I did read the DR briefly.  Perhaps I should add some conditional
compilation so that __x is converted using value_type() only when
using Sun C++?  That would limit the scope of the change and the
issue only relates to this compiler anywho.

Or should I just skip it entirely and leave the warnings as they
are?

Brad.

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