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(SRFI-19 Time/Date conversions): In default
tz-offset, note restrictions on a 32-bit system.
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@ -1718,12 +1718,23 @@ Convert between dates, times and days of the respective types. For
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instance @code{time-tai->time-utc} accepts a @var{time} object of type
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@code{time-tai} and returns an object of type @code{time-utc}.
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For conversions to dates, @var{tz-offset} is seconds east of
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Greenwich. The default is the local timezone, at the given time, as
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provided by the system.
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The @code{!} variants may modify their @var{time} argument to form
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their return. The plain functions create a new object.
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For conversions to dates, @var{tz-offset} is seconds east of
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Greenwich. The default is the local timezone, at the given time, as
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provided by the system, using @code{localtime} (@pxref{Time}).
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On 32-bit systems, @code{localtime} is limited to a 32-bit
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@code{time_t}, so a default @var{tz-offset} is only available for
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times between Dec 1901 and Jan 2038. For prior dates an application
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might like to use the value in 1902, though some locations have zone
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changes prior to that. For future dates an application might like to
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assume today's rules extend indefinitely. But for correct daylight
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savings transitions it will be necessary to take an offset for the
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same day and time but a year in range and which has the same starting
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weekday and same leap/non-leap (to support rules like last Sunday in
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October).
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@end defun
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@node SRFI-19 Date to string
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