Asking SRFI-19 to perform a UTC-to-TAI conversion for an ordinary day in 1960:
scheme@(guile-user)> (use-modules (srfi srfi-19)) scheme@(guile-user)> (time-utc->time-tai (date->time-utc (make-date 0 0 0 12 14 3 1960 0))) $1 = #<time type: time-tai nanosecond: 0 second: -309268800> The answer given is incorrect. Unlike previous conversion bugs where it was necessary to perform some arithmetic to reveal that the conversion had gone wrong, in this case the answer can be declared wrong without any detailed interpretation of the TAI time structure. It is incorrect for this conversion to return any specific TAI time, upon which arithmetic could be performed, because UTC is not defined for any time prior to 1961. The only sane behaviour is for the conversion to signal an error. The same goes for time-tai->time-utc, which at present accurately inverts time-utc->time-tai for the above time. -zefram
