Re: ioctl(2) vs sys/ioctl.h

[der Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> There is a bigger problem, the 'int' and 'void *' arguments might be
> passed in different ways then '...' is specified.

True, but it is not inherently a problem; it just complicates the
implementation of ioctl(), since it then has to not just pass down a
data pointer, but pass down enough information for the particular
ioctl's implementation to find whatever type the actual argument is.
(As it is, the implementation already depends on a nonportability,
basically that all pointer types are "the same".  It would explode
badly on a machine where some but not all pointer types are larger than
a machine word/register.)

> We only get away with it on our 64 bit archs because they all pass
> the first 3 arguments in registers.

...and are all byte-addressed.  If some pointers were 64 bits and
others were 128 (or, worse, 72 or 96 or some such), it would fall over
rather hard.

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