[Tutor] problem with time module

[Tim Peters]

[Dick Moores]
> OK, here's my reasoning. From the doc,
> 
> "mktime( t)
> 
> This is the inverse function of localtime(). Its argument is the
> struct_time or full 9-tuple (since the dst flag is needed; use -1 as the
> dst flag if it is unknown) which expresses the time in local time, not
> UTC. ...
> "

And it really is an inverse:  localtime() takes a timestamp and
converts to a local struct_time, while mktime() does exactly the
opposite.

> If mktime(t) is the inverse of localtime(), I thought this implied that
> the floating point number mktime(localtime()) returned would be
> seconds from the epoch based on my local time. I saw nothing that
> said that all timestamps are based on UTC (although I can see now
> that it's a Good Thing they are). I did understand that time() is based
> on UTC. Therefore I concluded that mktime(localtime()) should be
> about 7 hours less than time().

Unfortunately, the time module consists of thin wrappers around the
pretty miserable time functions defined by the C language.  That's why
"everyone knows" what "seconds from the epoch" <sheesh> means, and
"everyone knows" too that "seconds from the epoch" means UTC.  It
sucks, but that's life.  If it all possible, I'd encourage you to use
the newer datetime module instead.