On Thu, 5 Sep 2002, Hartvig Ekner wrote:
> I don't know the ultimate reasons why SGI choose ILP32 for n32, but one
> could certainly be portability.
It depends on how you define "portability". While it might help some
broken software, it will hurt good one.
> As defined, n32 provides all the benefits of 64-bit data (yes, you have
> to use long long to get to it), and 100% backward compatability with
So you can't use long to keep a file position pointer (off_t is quite a
new invention) and have to go for long long, for example? Weird and
definitely doesn't help portability.
> o32 sources that assume (sizeof(void *)) = sizeof(long), plus binary data
Thay should be fixed, instead. Using "void *" as a data container
doesn't work in general and one who does so should be banished. And the
other way round, there is no problem -- if one keeps 32-bit pointers in
64-bit longs, there is no bit loss.
> file compatability with o32 as all structures are exactly identical between
> o32 and n32.
Why don't use o32 as is then, instead of creating a slightly different
ABI? If some software needs binary data to be identical, then it has to
select fixed-size types, e.g. int32_t, explicitly. While int32_t and
friends are quite a new standard, other ways were used for years to set up
such aspects, e.g. autoconf, imake, hand-written system-specific
preprocessor macros, etc., etc.
--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +
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