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| Tapani Leppänen <leppanen_tap...@pine.sahako.fi> wrote:
>Hi,
>Is there an easy ( or any ) way to convert C-type time_t to
>Delphi-type TDateTime and vice versa ???
>TIA,
>Tapsa
>--
>Tapani Leppanen leppanen_tap...@pine.sahako.fi
>Heinola Sawmill Machinery Inc. Automation
I'll take a wild shot at it:
time_t is an unsigned long representing seconds elapsed since 1970.
TDateTime is a decimal representation of time, with the value to the
left of the decimal being a count of days elapsed since who knows
when, and the value to the right of the decimal being a fraction of a
day.
First, we'll need a reference: create a TDateTime variable for
0:00:00, 1970, using, I believe, StrToDate, and call that variable,
say, dt1970.
To convert from a TDateTime variable to time_t, subtract dt1970 from
your TDateTime variable, multiply by 24*60*60 (the number of seconds
in a day), and cast to an unsigned long (i.e., a time_t).
To convert from a time_t variable to a TDateTime, cast your time_t
variable to a TDateTime, divide by 24*60*60, and add dt1970.
That ought to do the trick.
P.S. ( If you're attempting to do conversions for dates prior to 1970,
you may need to consider a more advanced algorithm). |
