Re: [RFC v2 1/2] sys/types.h: Define new type: snseconds_t

[Joseph Myers <joseph@codesourcery.com>]

On Wed, 8 Dec 2021, Zack Weinberg via Libc-alpha wrote:

> On Tue, Dec 7, 2021, at 10:05 PM, Rich Felker wrote:
> > On Tue, Dec 07, 2021 at 09:26:59PM -0500, Zack Weinberg wrote:
> >> On Tue, Dec 7, 2021, at 7:29 PM, Rich Felker wrote:
> >> >
> >> > This is a non-starter because the relevant standards already require
> >> > the tv_nsec member to have type long.
> >> 
> >> That requirement is a defect in the standards, and I see no reason
> >> why this particular defect should be granted 'we're stuck with this'
> >> status.
> >
> > When the standard codifies existing *universal* practice without
> > introducing a gratuitous typedef
> 
> Universal practice is not necessarily correct.  It was an error to 
> define a structure type that's passed across the user/kernel boundary, 

"user/kernel boundary" is not a concept relevant to the standards; the 
standards deal with the *implementation* as a whole, all parts of which 
are expected to work together to implement features.

It was a defect when older XPG standards specified "long" for some fields 
in struct stat, because having st_blocks (for example) outside the range 
of 32-bit long is useful.  In the case of tv_nsec, all valid values fit 
within the range of 32-bit long and so that argument does not apply.

-- 
Joseph S. Myers
joseph@codesourcery.com