Thread: convert unix long time to get hour

This might help you:
http://www.oe.fau.edu/~lyann/watcom/.../strftime.html
http://www.oe.fau.edu/~lyann/watcom/...r.html#TimeFns

there is some unix source code out there that displays the time in this format

hrs:minutes:moth:day:year

now (5:47 PM) it would be displayed as
174705082002

Code:

#include <stdio.h>
#include <time.h>

int main ( void )
{
  struct tm *t;
  time_t now;
  now = time ( NULL );
  t = localtime ( &now );
  printf ( "%d:%d:%d\n", t->tm_hour, t->tm_min, t->tm_sec );
  return 0;
}

-Prelude

hmm

> hmm

Ok, I'm sorry. What's the point of these posts?

some strange infatuation methinks !!

anyway...

time.h function is "giving the time as set in the systems internal clock, seconds since jan 1st 1970". so i take it this is always the correct time ?? not the same as the time youve set on your pc obviously.

what about daylight saving times, times in different parts of the world etc. ??? its all programmed into the 'time chip' is it ??
ie mines in GMT. and will it automatically add and subtract an hour like the pc clock ?

just wondering......

Originally posted by stevey
time.h function is "giving the time as set in the systems internal clock, seconds since jan 1st 1970". so i take it this is always the correct time ?? not the same as the time youve set on your pc obviously.

I'm pretty sure all these functions use the time you've set on your pc. Somewhere there's a menu to change the time zone. It's either in your Clock's menu, or I think on older systems its under:
Start -> Settings -> Control Panel -> Regional Settings
I'm guessing the pc clock is always GMT, it simply displays the time based on your time zone.

Two time functions in C are localtime() and gmtime(), which convert the "seconds since jan 1st 1970" to either local time or GMT.

> I'm pretty sure all these functions use the time you've set on your pc.
Doesn't it have something to do with your system's BIOS?

having run Preludes code....

the time is obviously simply the time which is set on your pc, its not the correct time at all. just as near as can be expected, i mean its not a ceasium clock !! what was i thinking !!! i'm so dumb !! the time is kept on a chip, refreshed with your battery, but nothing but caesium clocks can keep correct time.

it is counting the seconds, but will be incorrect, all clocks need correcting from time to time.......and it auto changes daylight saving time etc and you adjust your own zone from GMT.

surprised windows doesn't have a time adjuster so when you go online it ensures your clock is correct, like those fancy wrist watches taking a radio signal.........

Ok, where's all the PC hardware experts out there? Help us out.

I would think this "seconds since jan 1st 1970" is stored in some nonvolatile memory, like EEPROM, unless they use a battery to keep the clock running.

Well, on my old 486 that I no longer have due to disassembling () the battery died. My brother, I believe, in the last few moments of that computers life replaced it with something much similar to a battery for a watch or something...I-dunno I just laughed at the situation. Anyhow, before hand when the battery was dying, everytime you managed to get it to boot up, it would ALWAYS ask you to input the date and time from dos. The same thing happened after we got the battery replaced and got it working. I believe the battery keeps power to the EEPROM or BIOS chips as swoopy said.

Alls I know is in the last few moments of the caputer's life, it had a nice shinny thing inside that said Energizer on it.