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From: John Reagan <johnrreagan@earthlink.net>
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Subject: Re: New VSI post on Youtube
Date: Wed, 21 Aug 2024 10:21:17 +0200
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On 8/15/2024 1:58 AM, Arne Vajhøj wrote:
> On 8/14/2024 7:47 PM, Lawrence D'Oliveiro wrote:
>> On Wed, 14 Aug 2024 14:33:27 -0400, Arne Vajhøj wrote:
>>> And it has different size of long and pointers.
>>
>> If you wanted an integer type that is compatible with pointers, that was
>> always intptr_t and uintptr_t, surely
> 
> 
> I am not being particular clear.
> 
> I am not saying that:
> 
> default sizeof long C++ x64 <> default sizeof pointer C++ x64
> 
> I am saying that:
> 
> default sizeof long C++ x64 <> default sizeof long C++ Itanium & Alpha
> default sizeof pointer C++ x64 <> default sizeof pointer C++ Itanium & 
> Alpha
> 
> and later:
> 
> default sizeof long C++ x64 <> default sizeof long C x64
> default sizeof pointer C++ x64 <> default sizeof pointer C x64
> 
> Arne
> 
> 
> 
Yes, all good points.  The size_t and offset_t = 32-bits and ptrdiff_t = 
32-bits on Alpha/Itanium started the mess years ago.

Personally, I would have kept all the defaults the same as Itanium but 
got "convinced" to go wider.  The first attempt was ONLY 64-bit pointers 
on x86 with C++ but things like those pesky descriptors and itemlists 
got in the way.

I did suggest an LP64, ILP32, etc qualifier but mostly got blank stares 
from other engineers as "too nerdy"

long == 64-bits has caused us to make changes as prior header writers 
assumed that long was 32-bits.  They should have all followed Arne's 
advice and used int32_t and int64_t when specifying their ABIs.

I'll can take some ownership on the changes, but I suffered with years 
of "John, why is size_t 32-bits?  Why does subtracting two 64-bit 
pointers only give me a 32-bit result?"