Re: git.git object database at kernel.org?

From: H. Peter Anvin <hpa@zytor.com>
Date: Apr 26, 2005, 00:48 UTC
Message-ID: <426D8FDF.5050608@zytor.com>
In-Reply-To: <Pine.LNX.4.58.0504251729080.18901@ppc970.osdl.org>

Linus Torvalds wrote:

Show 18 quoted lines

> 
> On Mon, 25 Apr 2005, H. Peter Anvin wrote:
> 
>>No, mktime() always uses the local time zone.  It's the inverse of 
>>localtime().
> 
> Note that this still doesn't make any sense.
> 
> A true inverse of "localtime()" should still take the GMT offset from
> "struct tm", and it would work fine, assuming that localtime() set that
> offset correctly.
> 
> So _I_ think it's incredibly stupid that mktime() looks at the local 
> timezone. 
> 
> Oh, well.  Not a big issue except for the date conversion, and since there 
> hopefully aren't any old repo's left, we can leave it behind us.
>

It *is* incredibly stupid, but dates back to the fact that a the GMT offset field in struct tm is a reasonably recent invention, and a lot of old code depended on just stuffing fields in struct tm and calling mktime(); they would leave the offset field uninitialized, as opposed to setting it to some well-defined "I don't know" value.

What totally blows is that if mktime() can't be fixed, that we haven't added mktime_have_offset() or something like that.

Oh well.  If you have the offset, the algorithm is fully arithmetric and 
doesn't rely on the zoneinfo system, so it can be trivially implemented. 
   And again, curl_gettime() does handle the whole string to time_t 
conversion of the common formats.

	-hpa