[R] ISOdate returns incorrect date?

[Heiko Schaefer]

Dear all,

I have found the following (for me) incomprehensible behaviour of
ISOdate (POSIXct):
> ISOdate(1900,6,16)
[1] "1900-06-15 14:00:00 Westeuropäische Sommerzeit"
> ISOdate(1950,6,16)
[1] "1950-06-16 14:00:00 Westeuropäische Sommerzeit"

Note that in the first case I get the 15th of June back, not the 16th as
I would have expected!
This happened under R-1.7.1 on both windows and linux.

I would greatly appreciate your comments,

Heiko