doc: /* Return the current time, as a float number of seconds since the epoch.
If SPECIFIED-TIME is given, it is the time to convert to float
instead of the current time. The argument should have the form
-(HIGH LOW . IGNORED). Thus, you can use times obtained from
+(HIGH LOW) or (HIGH LOW USEC). Thus, you can use times obtained from
`current-time' and from `file-attributes'. SPECIFIED-TIME can also
have the form (HIGH . LOW), but this is considered obsolete.