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| -rw-r--r-- | Doc/lib/libtime.tex | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/Doc/lib/libtime.tex b/Doc/lib/libtime.tex index f63ecb0..6cab3a9 100644 --- a/Doc/lib/libtime.tex +++ b/Doc/lib/libtime.tex @@ -26,9 +26,22 @@ determined by the C library; for \UNIX{}, it is typically in 2038.% \index{Year 2038} \item -Year 2000 (Y2K) issues: Python depends on the platform's C library, +\strong{Year 2000 (Y2K) issues}: Python depends on the platform's C library, which generally doesn't have year 2000 issues, since all dates and -times are represented internally as seconds since the epoch.% +times are represented internally as seconds since the epoch. +Functions accepting a time tuple (see below) generally require a +4-digit year. For backward compatibility, 2-digit years are supported +if the module variable \code{accept2dyear} is a non-zero integer; this +variable is initialized to \code{1} unless the environment variable +\code{PYTHONY2K} is set to a non-empty string, in which case it is +initialized to \code{0}. Thus, you can set \code{PYTHONY2K} in the +environment to \code{x} to require 4-digit years for all year input. +When 2-digit years are accepted, they are converted according to the +POSIX or X/Open standard: values 69-99 are mapped to 1969-1999, and +values 0--68 are mapped to 2000--2068. Values 100--1899 are always +illegal. Note that this is new as of Python 1.5.2(a2); earlier +versions, up to Python 1.5.1 and 1.5.2a1, would add 1900 to year +values below 1900.% \index{Year 2000}% \index{Y2K} |