Re: [boost] alignment?

From: John Max Skaller (skaller_at_[hidden])
Date: 2001-05-03 09:51:17

John Maddock wrote:
> 
> >but the constant value of '_MAX_ALIGN' must be set
> >manually by the client. This isn't really acceptable.
> >It would be useful if an appropriate value were available
> >in the boost library.
> 
> I don't think it can be unambiguously calculated, but given:
> 
> union max_align
> {
> int i;
> long l;
> long long ll;
> double d;
> long double ld;
> };
> 
> Then:
> 
> boost::alignment_of<max_align>::value
> 
> should be somewhere near it.

        Since the calculation isn't definite, I'd prefer to see
a constant

        MAX_ALIGN

        or perhaps 

        boost::max_align

included in the library somewhere. I must repeat that this
value is absolutely fundamental to all routines that
suballocate memory. In particular, I noticed a 
Pool suballocator in boost: it cannot possibly be portable ISO C++
without this constant. It's a requirement of any allocator that
the returned address be suitable for instantiating _any_ data type.

-- 
John (Max) Skaller, mailto:skaller_at_[hidden]
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