Same thing happens on OS X. A bit of googling (did you know that Jimi Hendrix and the Band of Gypsies played at the Fillmore East on December 31, 1969?) reveals that the root issue is that mktime() returns -1 if the calendar time cannot be represented, which makes the case where the time _can_ be represented as -1 a bit tricky!
People have come up with heuristics to detect this case, but I wonder if it's worth it. Take a look at http://stackoverflow.com/questions/14049047/unix-c-get-time-at-a-different-zone There has to be a simpler way, though. -pd On Apr 17, 2013, at 22:10 , William Dunlap wrote: > A user here noticed the following difference between Linux and Windows > versions > of R-2.15.3 (and R-3.0.0, I think) when using times within a second of the > end of 1969: > > f <- function (sec = -1) > { > x1 <- as.POSIXct(c(2 * sec, sec, 0), origin = "1970-01-01", tz = "UTC") > x2 <- as.POSIXlt(x1) > x3 <- as.POSIXct(x2, origin = "1970-01-01", tz = "UTC") > list(x1 = x1, x2 = x2, x3 = x3) > } > > On Windows I get: >> f(-1) > $x1 > [1] "1969-12-31 23:59:58 UTC" > [2] "1969-12-31 23:59:59 UTC" > [3] "1970-01-01 00:00:00 UTC" > > $x2 > [1] "1969-12-31 23:59:58 UTC" > [2] "1969-12-31 23:59:59 UTC" > [3] "1970-01-01 00:00:00 UTC" > > $x3 > [1] "1969-12-31 23:59:58 UTC" > [2] "1969-12-31 23:59:59 UTC" > [3] "1970-01-01 00:00:00 UTC" > > On Linux I get an NA in x3 for 1 second before 1970: >> f(-1) > $x1 > [1] "1969-12-31 23:59:58 UTC" > [2] "1969-12-31 23:59:59 UTC" > [3] "1970-01-01 00:00:00 UTC" > > $x2 > [1] "1969-12-31 23:59:58 UTC" > [2] "1969-12-31 23:59:59 UTC" > [3] "1970-01-01 00:00:00 UTC" > > $x3 > [1] "1969-12-31 23:59:58 UTC" > [2] NA > [3] "1970-01-01 00:00:00 UTC" > > On Windows, sessionInfo() is > R version 2.15.3 (2013-03-01) > Platform: x86_64-w64-mingw32/x64 (64-bit) > > locale: > [1] LC_COLLATE=English_United States.1252 LC_CTYPE=English_United > States.1252 > [3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C > > [5] LC_TIME=English_United States.1252 > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > > On Linux, sessionInfo() is >> sessionInfo() > R version 2.15.3 (2013-03-01) > Platform: x86_64-unknown-linux-gnu (64-bit) > > locale: > [1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C > LC_TIME=en_US.UTF-8 > [4] LC_COLLATE=en_US.UTF-8 LC_MONETARY=en_US.UTF-8 > LC_MESSAGES=en_US.UTF-8 > [7] LC_PAPER=C LC_NAME=C LC_ADDRESS=C > [10] LC_TELEPHONE=C LC_MEASUREMENT=en_US.UTF-8 > LC_IDENTIFICATION=C > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > > Bill Dunlap > Spotfire, TIBCO Software > wdunlap tibco.com > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
