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Re: source(builtin) and read(2)
From: |
Geoff Clare |
Subject: |
Re: source(builtin) and read(2) |
Date: |
Sat, 31 Mar 2007 10:10:11 +0100 |
User-agent: |
Mutt/1.5.9i |
Matthew Woehlke <address@hidden> wrote, on 30 Mar 2007:
>
> Geoff Clare wrote:
> >The code was just to illustrate the point that if it is possible for
> >the condition (var > SSIZE_MAX) to be true then the implementation
> >does not conform to the requirement that SSIZE_MAX is the maximum
> >value of an object of type ssize_t.
>
> I still don't buy that. If that was the intended meaning then I would
> expect the standard to read "...maximum value of a ssize_t" or "maximum
> value of *type* ssize_t". It doesn't. It uses the word "object" in this
> one, and ONLY one, instance. If this was *not* done to create a
> distinction between representable and permissible values, then why *was*
> it done?
The wording difference is accidental. The 1990 standard did not
describe CHAR_MAX, INT_MAX, etc. at all, it just listed them as
limits from the C Standard that were required by POSIX.1. Thus
SSIZE_MAX was the only limit of that kind that had a description
in POSIX.1-1990.
There are variations in the wording for the other limits as well.
E.g. CHAR_MAX is "Maximum value of type char", but INT_MAX is
"Maximum value of an int". There is no significance to any of
these variations.
Interestingly the wording for SSIZE_MAX in 1990 was slightly
different: "The maximum value that can be stored in an object of
type ssize_t". The current wording seems to have come from XPG4.
Since XPG4 deferred to POSIX.1-1990, there would have been no
intended difference in requirements.
--
Geoff Clare <address@hidden>
The Open Group, Thames Tower, Station Road, Reading, RG1 1LX, England
Re: source(builtin) and read(2), Paul Eggert, 2007/03/30
- Re: source(builtin) and read(2), Geoff Clare, 2007/03/30
- Re: source(builtin) and read(2), Paul Eggert, 2007/03/30
- Re: source(builtin) and read(2), Geoff Clare, 2007/03/31
- Re: source(builtin) and read(2), Paul Eggert, 2007/03/31
- Re: source(builtin) and read(2), James Youngman, 2007/03/31