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Release Notes

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Andrew Johnson
2019-06-07 15:37:46 -05:00
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<h3>Replace EPICS_TIMEZONE with EPICS_TZ</h3>
<p>The <tt>EPICS_TIMEZONE</tt> environment parameter provided time-zone
information for the IOC's locale in the old ANSI format expected by VxWorks for
its <tt>TIMEZONE</tt> environment variable, and can also used by RTEMS to set
its <tt>TZ</tt> environment variable. However the <tt>TIMEZONE</tt> value has to
be updated every year since it contains the exact dates of the daylight-savings
time changes. The Posix TZ format that RTEMS uses contains rules that for
calculating those dates, thus its value would only need updating if the rules
(or the locale) are changed.</p>
<p>This release contains changes that replace the <tt>EPICS_TIMEZONE</tt>
environment parameter with one called <tt>EPICS_TZ</tt> and a routine for
VxWorks that calculates the <tt>TIMEZONE</tt> environment variable from the
current <tt>TZ</tt> value. This routine will be run once at start-up, when the
EPICS clock has synchronized to its NTP server. The calculations it contains
were worked out and donated to EPICS by Larry Hoff in 2009; it is unforunate
that it has taken 10 years for them to be integrated into Base.</p>
<p>The default value for the <tt>EPICS_TZ</tt> environment parameter is set in
the Base configure/CONFIG_SITE_ENV file, which contains example settings for
most EPICS sites that use VxWorks, and a link to a page describing the Posix TZ
format for any locations that I missed.</p>
<p>If a VxWorks IOC runs continuously without being rebooted from December 31st
to the start of daylight savings time the following year, its <tt>TIMEZONE</tt>
value will be wrong as it was calculated for the previous year. This only
affects times that are converted to a string on the IOC however and is easily
fixed; just run the command <tt>tz2timezone()</tt> on the VxWorks shell and the
calculation will be redone for the current year. IOCs that get rebooted at least
once before the start of summer time will not need this to be done.</p>
<h3>Cleaning up with Multiple CA contexts in a Process</h3>
<p>Bruno Martins reported a problem with the CA client library at shutdown in a