Path: utzoo!attcan!uunet!lll-winken!uwm.edu!zaphod.mps.ohio-state.edu!think!mintaka!bloom-beacon!eru!luth!sunic!mcsun!unido!mpirbn!p554mve
From: p554mve@mpirbn.UUCP (Michael van Elst)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Setting the Amiga system date and time
Message-ID: <559@mpirbn.UUCP>
Date: 18 Feb 90 10:30:20 GMT
References: <1113@mindlink.UUCP>
Reply-To: p554mve@mpirbn.UUCP (Michael van Elst)
Organization: Max-Planck-Institut fuer Radioastronomie, Bonn
Lines: 95

In article <1113@mindlink.UUCP> a218@mindlink.UUCP (Charlie Gibbs) writes:
>In article <77.25d0c638@intersil.uucp> hamilton@intersil.uucp
>(Fred Hamilton) writes:
>>I can read the Amiga system time with DateStamp().
>>But how do I SET it?
>>Thanks.  (I'm installing a battery backed up clock in my 1000.)
>
>     I couldn't figure it out either, so I cheated - I just built
>an appropriate DATE command and Execute()d it.  Working in assembly
>language I got my program down to 400 bytes.

I tried to mail to the orignal poster but did not succeed. Here comes
the letter.

> By the way, I re-mapped my clock to $980000 and it works great.  I still
> haven't figured out how to set the Amiga system time from within a C
> program (I'm new to C and all these structures, DoIO calls, and lousy
> documentation are really making my brain hurt), but I can set my clock 
> to the Amiga system time and dump it to verify that it works.

Hello, you should get the new manuals (the complete set is the stores
for about 4 weeks). It's not easy for a C novice but the examples will
say you much about C and Amiga programming.

Now, for your question. The system clock is managed by the timer.device.
You should open the device for unit UNIT_VBLANK. Then use the
TR_SETSYSTIME command to set the date and time. You'll need to convert
date/time into system time which is seconds and microseconds since
1.january 1978 0:00. (Is the year correct ? Hmm)

Example:

#include <devices/timer.h>

struct timerequest *treq;
struct MsgPort *port;

/* create an IO reply port */
port = CreatePort(0,0);
if (port == NULL)
	cleanup("can't get io reply port");

/* create the IO message */
treq = (struct timerequest *)CreateExtIO(port,sizeof(struct timerequest))
if (treq == NULL)
	cleanup("can't get timer request");

/* get access to the timers */
if (OpenDevice(TIMERNAME, UNIT_VBLANK, treq, 0))
	cleanup("can't open timer.device");

/* and now set the system time, seconds and micros should be the
   time you want to set */
treq.tr_node.io_Command = TR_SETSYSTIME;
treq.tr_time.tv_secs = seconds;
treq.tr_time.tv_micro = micros;
DoIO(treq);

/* and free all resources */
CloseDevice(treq);
DeleteExtIO(treq);
DeletePort(port);

---------------------

Most of the code is needed only once in a real program, you may
use the same timerequest over and over again. Oh, and cleanup()
doesn't exist. I use one routine that frees all the resources I've
claimed throughout the whole program, it something like:

cleanup(message)
char *message;
{
	if (treq != NULL && treq->tr_node.io_Device != -1) CloseDevice(treq);
	if (treq != NULL) DeleteExtIO(treq);
	if (port != NULL) DeletePort(port);

	if (s != NULL) fprintf(stderr,"cleanup: %s\n",message);
}

If you want to read the current system time then use instead:

treq.tr_node.io_Command = TR_GETSYSTIME;
DoIO(treq);
seconds = treq.tr_time.tv_secs;
micros = treq.tr_time.tv_micro;

----------------------
And I recommend it a second time, all the information is in the Rom Kernal
Manuals.
-- 
					Michael van Elst

E-Mail: uunet!unido!mpirbn!p554mve
Internet: p554mve@mpirbn.UUCP