X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f
From: Leszek Matok <nowiny AT Lam DOT pl>
Newsgroups: comp.os.msdos.djgpp
Subject: gettimeofday( ) reports time 24 hours in the future at 0:00
Date: Thu, 01 Jun 2006 02:25:06 +0200
Organization: tp.internet - http://www.tpi.pl/
Lines: 55
Message-ID: <1149121505.3843.30.camel@pensja.lam.pl>
NNTP-Posting-Host: pc7.siedlce.sdi.tpnet.pl
Mime-Version: 1.0
Content-Type: multipart/mixed; boundary="=-WCqcEmrRQeycEAp158U9"
X-Trace: nemesis.news.tpi.pl 1149121636 28622 217.96.220.7 (1 Jun 2006 00:27:16 GMT)
X-Complaints-To: usenet AT tpi DOT pl
NNTP-Posting-Date: Thu, 1 Jun 2006 00:27:16 +0000 (UTC)
X-Mailer: Evolution 2.6.1 (2.6.1-1.fc5.2) 
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com


--=-WCqcEmrRQeycEAp158U9
Content-Type: text/plain
Content-Transfer-Encoding: 7bit

I'm attaching a tiny C program showing gettimeofday( ) being broken in
DJGPP (version "djdev203 Development Kit and Runtime (June 2002
Refresh)"). I run it under FreeDOS in dosemu, but the problem was first
spotted by my friend under Windows XP, so it's not something
OS-dependant.

The problem is that at 0:00, when the date changes, gettimeofday( )
reports next day, but still 23:59. I guess it's taking time before date
from system clock and the date can change between the calls with clock
change (from 23:59 to 0:00) isn't noticed, than it builds struct timeval
from wrong data. If I'm right, the fix would be to first grab date, then
time, then date again (date changes very rarely compared to time) and if
the date differs, time again :)

My program sets the time to 23:59:59 yesterday, then grabs the time
again and again and again, until one second later, when the day changes
and the error manifests itself:

C:\TEST>test
t1: 1149206399, Thu Jun  1 23:59:59 2006
t2: 1149120000, Thu Jun  1 00:00:00 2006

This happens every single time I run the attached program.

Of course, in real life, for my real program, this happens once per day
or two, but I guess my program isn't the only one depending on
gettimeofday( ) returning proper time. Is it fixed in cvs? Or can it
somehow be my error? :)

Lam

--=-WCqcEmrRQeycEAp158U9
Content-Description: 
Content-Disposition: inline; filename=test.c
Content-Type: text/x-csrc; charset=UTF-8
Content-Transfer-Encoding: base64

I2luY2x1ZGUgPHN5cy90aW1lLmg+DQojaW5jbHVkZSA8dGltZS5oPg0KI2luY2x1ZGUgPHN0ZGlv
Lmg+DQoNCmludCBtYWluKCB2b2lkICkNCnsNCiAgICBzdHJ1Y3QgdGltZXZhbCB0djsNCiAgICB0
aW1lX3QgdDEsIHQyOw0KDQogICAgdHYudHZfc2VjID0gMTE0OTExOTk5OTsNCiAgICB0di50dl91
c2VjID0gMDsNCiAgICBzZXR0aW1lb2ZkYXkoICZ0diwgMCApOw0KDQogICAgdDEgPSAwOw0KICAg
IHdoaWxlICggMSApDQogICAgew0KCWdldHRpbWVvZmRheSggJnR2LCAwICk7DQoJdDIgPSB0di50
dl9zZWM7DQoJaWYgKCB0MiA8IHQxICkNCgkgICAgYnJlYWs7DQoJdDEgPSB0MjsNCiAgICB9DQoN
CiAgICBwcmludGYoICJ0MTogJWQsICVzIiwgdDEsIGFzY3RpbWUoIGxvY2FsdGltZSggJnQxICkg
KSApOw0KICAgIHByaW50ZiggInQyOiAlZCwgJXMiLCB0MiwgYXNjdGltZSggbG9jYWx0aW1lKCAm
dDIgKSApICk7DQogICAgcmV0dXJuIDA7DQp9DQo=


--=-WCqcEmrRQeycEAp158U9--