From: Robert Dewar <dewar@gnat.com>
Subject: Re: Ada Calendar oddity <was Re: C date package>
Date: 2000/05/21
Date: 2000-05-21T00:00:00+00:00 [thread overview]
Message-ID: <8g8on6$a0v$1@nnrp1.deja.com> (raw)
In-Reply-To: 3924D3FF.11D8C99A@earthlink.net
In article <3924D3FF.11D8C99A@earthlink.net>,
"Robert I. Eachus" <rieachus@earthlink.net> wrote:
(Changing the
> range
> for Year_Number would require a different representation for
variables
> of type Calendar.Time. This is simething that needs to be
done slowly,
> and with plenty of warning to the compiler vendors.) On the
other hand,
> a new Long_Time type would cause fewer upward compatibility
problems.
What really *is* the situation with Ada 95 compilers. Certainly
in GNAT we chose a representation for Calendar.Time that can
accomodate very wide ranges of times and dates (Calendar.Time
is kept in units of nanoseconds stored in a signed 64 bit value
which represents very wide time ranges -- tens of thousands of
years at least).
It certainly is the case that representations of Calendar.Time
are the worrisome thing here (think for example of such values
written on files). A compiler that has chosen a narrow range
representation for this type has, in my view, made a significant
mistake which will cause nasty compatibility problems later,
but I don't know specifically that any compilers have made
this choice.
Anyone know what other Ada 95 compilers do?
Robert Dewar
Ada Core Technologies
Sent via Deja.com http://www.deja.com/
Before you buy.
next prev parent reply other threads:[~2000-05-21 0:00 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <l0313030eb53d1408aee7@[144.205.16.58]>
2000-05-09 0:00 ` C date package Geoff Bull
2000-05-09 0:00 ` Geoff Bull
2000-05-09 0:00 ` Robert Dewar
2000-05-10 0:00 ` Geoff Bull
2000-05-10 0:00 ` Robert Dewar
2000-05-10 0:00 ` Ken Garlington
2000-05-10 0:00 ` Geoff Bull
2000-05-10 0:00 ` Geoff Bull
2000-05-10 0:00 ` Ada Calendar oddity <was Re: C date package> Preben Randhol
2000-05-10 0:00 ` Tarjei Tj�stheim Jensen
2000-05-11 0:00 ` Geoff Bull
2000-05-11 0:00 ` Gautier
2000-05-12 0:00 ` Geoff Bull
2000-05-12 0:00 ` Gautier
2000-05-11 0:00 ` Al Christians
2000-05-11 0:00 ` Charles Hixson
2000-05-11 0:00 ` Tarjei Tj�stheim Jensen
2000-05-12 0:00 ` Charles Hixson
2000-05-12 0:00 ` Tarjei Tj�stheim Jensen
2000-05-10 0:00 ` Robert A Duff
2000-05-10 0:00 ` Preben Randhol
2000-05-10 0:00 ` Charles Hixson
2000-05-11 0:00 ` Geoff Bull
2000-05-11 0:00 ` Charles Hixson
2000-05-12 0:00 ` Geoff Bull
2000-05-17 0:00 ` Robert I. Eachus
2000-05-19 0:00 ` Geoff Bull
2000-05-19 0:00 ` Robert I. Eachus
2000-05-21 0:00 ` Robert Dewar [this message]
2000-05-21 0:00 ` Robert Dewar
[not found] ` <392869F0.D88F056A@acenet.com.au>
2000-05-22 0:00 ` Tarjei Tj�stheim Jensen
2000-05-27 0:00 ` Reinert Korsnes
2000-05-27 0:00 ` Tarjei Tj�stheim Jensen
2000-06-03 0:00 ` Robert I. Eachus
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