On Thu, Nov 27, 2014 at 10:50:26 +0000, Edmund Grimley Evans wrote:
> http://wiki.debian.org/ArchitectureSpecificsMemo
>
> Some suggestions for improving this table:
>
> 1. About half of the table is taken up with sizeof information, some
> of which could be expressed more concisely. (Are all Debian
> architectures ILP32 or LP64? Any rare exceptions could be described in
> a footnote.)
>
> 2. Perhaps it would be better to reverse the axes, particularly if the
> sizeof information is simplified and as more and more architectures
> are added.
>
> 3. A link to a list of system calls might be useful for some people.
>
> 4. I'd like to see some information about va_list added as this
> sometimes causes portability problems. For example:
>
> On amd64, va_list is a (struct { ... } [1]) with size 24 and alignment
> 8. (It's an array, so it turns into a pointer in some circumstances.
> You can test whether a va_list is equal to zero, for example.)
>
> On arm64, va_list is a (struct { ... }) with size 32 and alignment 8.
> (It's not an array. You can't test whether it's zero.)
>
> On armhf, va_list is a (struct { ...}) with size 4 and alignment 4.
> (Have I got that right?)
>
> On i386, va_list is a (char *).
>
> Any thoughts? Vehement objections?
>
As this is one of the wiki pages that I visit most often: I'd completely agree,
and addition it would be very useful if the macros defined by compilers we use
(GCC, and maybe Clang) to test for a particular architecture were listed as
well. (Yes, we're in do-ocracy, so I should just go and add these...)
Best,
Michael
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