Newsgroups: comp.std.c
Path: utzoo!utgpu!jarvis.csri.toronto.edu!dgp.toronto.edu!flaps
From: flaps@dgp.toronto.edu (Alan J Rosenthal)
Subject: Re: The type of time_t (was: struct tm -> time_t converter wanted)
Message-ID: <8810231738.AA04205@explorer.dgp.toronto.edu>
Organization: University of Toronto
References: <442@grand.UUCP> <8700@smoke.BRL.MIL> <6964@cdis-1.uucp> <9816@haddock.ima.isc.com> <1988Oct22.230215.19411@utzoo.uucp>
Date: Sun, 23 Oct 88 13:38:52 EDT


karl@haddock.ima.isc.com (Karl Heuer) writes:
>>There's nothing to prevent time_t from being typedef'd to unsigned long int,
>>which would double the range...

henry@utzoo.uucp (Henry Spencer) writes:
>Unfortunately, it would probably break a significant number of programs that
>think time_t is signed.  Those programs are arguably broken already, but some
>degree of pragmatism is necessary in such matters.

Is it possible to assume that time_t is signed without assuming it's either
int or long (or char)?  I can't see how, and if it's not then Karl's change
above wouldn't break any more programs than changing time_t between int and
long would.

(It is true that a cast to long sort of assumes that the value cast is signed,
but in the case of time_t I don't see what you want to do with that value
except cast it back to time_t, which makes the cast to long rather pointless.
Or if you want to printf the number, well ansi printf's %lu format takes a
long, not an unsigned long, anyway, so the cast to long is the correct way to
print unsigned longs as well as longs.)

ajr

--
#define __STDC__ 0