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From "Eric Lemings" <Eric.Lemi...@roguewave.com>
Subject RE: [STDCXX-709] ContainerData ctor and UserClass::from_char()
Date Thu, 27 Mar 2008 20:07:20 GMT
 

> -----Original Message-----
> From: Eric Lemings 
> Sent: Thursday, March 27, 2008 2:05 PM
> To: 'dev@stdcxx.apache.org'
> Subject: RE: [STDCXX-709] ContainerData ctor and 
> UserClass::from_char()
> 
>  
> 
> > -----Original Message-----
> > From: Martin Sebor [mailto:sebor@roguewave.com] 
> > Sent: Wednesday, March 26, 2008 4:19 PM
> > To: dev@stdcxx.apache.org
> > Subject: Re: [STDCXX-709] ContainerData ctor and 
> > UserClass::from_char()
> > 
> ...
> > 
> > It seems pretty clear that somewhere between the call TO
> > operator new and the return FROM the function the pointer
> > gets bumped up by 8 on LP64 (and 4 on ILP32 according to
> > your observation). The only thing in between these two
> > steps is the call to the UserClass ctor. So unless the
> > ctor manages to change its own this pointer we're looking
> > as a compiler bug. Either way, we need a small, isolated
> > test case to understand how to deal with it...
> > 
> > Martin
> 
> The pointer is being adjusted before the constructor is
> called.
> 
> I was looking yesterday at GCC's implementation of the
> C++ ABI __cxa_vec_new2() function.  There's a padding
> argument that may be utilized in HP-UX aCC 6.x for some
> unknown reason.
> 
> Also, I thought the allocator in _rw_dispatch(), where
> the ContainerTestCaseData object is being constructed,
> could play some role in all this but looks like its
> only used in the test function.
> 
> Brad.

Does HP-UX IPF have any sort of memory alignment restrictions
that anyone is aware of?

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