Local time_t

[anonytmouse]

I need a 'local time_t'. Currently, I've got the following code. Anyone got better code that won't crap out at dst changing time?

// Work out the time adjustment for this timeT...
if ( (ptm = gmtime(&timeT)) == NULL ) return E_FAIL;
if ( (timeTTemp = mktime(ptm)) == (time_t) -1 ) return E_FAIL;

timeT = (timeT - timeTTemp);

Thanks.

[anonytmouse]

Well, I think I have a working solution. Can anybody see any situation where this will fail?

	localtm = *localtime(&timeT);
	utctm = *gmtime(&timeT);

	localtm.tm_isdst = 0;
	utctm.tm_isdst = 0;

	timeTLocal = mktime(&localtm);
	timeTUtc = mktime(&utctm);

	timeT += timeTLocal - timeTUtc;

It basically gets the broken down local and gmt time and then uses mktime to get time_t's so the difference can be found. isdst is set to 0 so they both should be adjusted by the same amount in calls to mktime.

[twm]

>timeT += timeTLocal - timeTUtc;
difftime, perhaps?

timeT += difftime(timeTLocal, timeTUtc);

[anonytmouse]

>difftime, perhaps?

Why?

[twm]

>Why?
Because you don't know how time_t may be represented and it describes your intentions more clearly.