Bug 57319

Summary:	mktime tm_isdst bug
Product:	[Retired] Red Hat Linux	Reporter:	Tim Waugh <twaugh>
Component:	glibc	Assignee:	Jakub Jelinek <jakub>
Status:	CLOSED NOTABUG	QA Contact:	Aaron Brown <abrown>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	8.0	CC:	alan, fweimer
Target Milestone:	---
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Hardware:	i386
OS:	Linux
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Fixed In Version:		Doc Type:	Bug Fix
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Last Closed:	2003-04-24 07:23:00 UTC	Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description Tim Waugh 2001-12-10 11:06:07 UTC

Description of Problem:
mktime seems to treat tm_isdst oddly.


They are surely the same time?  The difference between the mktime
calls is that for the former, tm_isdst is set to 0, while for the
latter it is -1.  If I try 'BST' (with tm_isdst==1), I also get
-3600.

Version-Release number of selected component (if applicable):
glibc-2.2.4-19

How Reproducible:
100%

Steps to Reproduce:
1. date --date="1970-01-01 00:00 GMT" +%s
2. date --date="1970-01-01 00:00 UTC" +%s

Actual Results:
[tim@cyberelk tim]$ date --date="1970-01-01 00:00 GMT" +%s
-3600
[tim@cyberelk tim]$ date --date="1970-01-01 00:00 UTC" +%s
0

Expected Results:
Both should return 0, I think, since both times refer to the same instant.

Additional Information:
In /etc/sysconfig/clock ZONE is "Europe/London".

Comment 1 Alan Cox 2002-12-15 18:45:49 UTC

Confirmed still present in 8.0

Comment 2 Ulrich Drepper 2003-04-24 07:23:00 UTC

A little bit of British history: the UK was on UTC+1 from 1968 to 1971.  See
http://student.cusu.cam.ac.uk/~jsm28/british-time/.  Therefore the result you
see is exactly right.