From:	ftilley AT azstarnet DOT cyberbromo DOT com (Felix Tilley)
Newsgroups:	comp.os.msdos.djgpp
Subject:	strftime: Need Help with Time Offsets
Date:	Fri, 15 Dec 2000 07:07:52 GMT
Organization:	delete.spammers.org
Message-ID:	<3a39c060.1329770@corp.supernews.net>
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Lines:	120
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

This works fine under Linux Mandrake and some versions of HP-UX.  It
works under djgpp too, except for the GMT offsets.  The strftime %z %Z
formats do not appear to be uniform over the C/Unix/DOS/Linux
environments.

The program's output is first, very simple followed by the source
code.



PROGRAM OUTPUT:

FET>
FET> ./a.out
Fri, 15 Dec 2000 07:01:31 +000
Fri, 15 Dec 2000 00:01:31 -000
Fri, 15 Dec 2000 02:01:31 -000
Fri, 15 Dec 2000 01:01:31 -000
Thu, 14 Dec 2000 23:01:31 -000
Fri, 15 Dec 2000 15:01:31 +288
FET>


All of the GMT offsets are wrong.  Dates and times are correct, but
the GMT offsets are wrong.



Source code is:

/* Test of date formatting */

#include "stdio.h"
#include "string.h"
#include "stdlib.h"
#include "time.h"

main ()
{
time_t tnum, tmpnum;
struct tm *tmdate;
char *sdate[256], *dstring;
char *whatidstr="\n@(#) Prints Several TZ's   17 NOV 2000\n";
char *fmt= "%a, %d %b %Y %X %z %Z";

time(&tnum);				/* Get Machine Time */

tmdate=gmtime(&tnum);		/* Get and print GMT */
/*
dstring=asctime(tmdate);
printf("GMT\n%s", dstring);
*/
strftime( (char*) sdate, 200, fmt, tmdate);
printf ("%s\n", sdate);


tmdate=localtime(&tnum);	/* Get and print local time */
/*
dstring=asctime(tmdate);
printf("LOCAL\n%s", dstring);
*/
strftime( (char*) sdate, 200, fmt, tmdate);
printf ("%s <--\n", sdate);


tmdate=gmtime(&tnum);				/* GMT again */
tmdate->tm_hour=tmdate->tm_hour - 5;		/* GMT -0500  EST  */
tmdate->tm_gmtoff= -5*3600;
tmdate->tm_zone="EST";
mktime (tmdate);
tmdate->tm_gmtoff= -5*3600;
tmdate->tm_zone="EST";
strftime( (char*) sdate, 200, fmt, tmdate);
printf ("%s\n", sdate);

tmdate=gmtime(&tnum);				/* GMT again */
tmdate->tm_hour=tmdate->tm_hour - 6;		/* GMT -0600  CST  */
tmdate->tm_gmtoff= -6*3600;
tmdate->tm_zone="CST";
mktime (tmdate);
tmdate->tm_gmtoff= -6*3600;
tmdate->tm_zone="CST";
strftime( (char*) sdate, 200, fmt, tmdate);
printf ("%s\n", sdate);

tmdate=gmtime(&tnum);				/* GMT again */
tmdate->tm_hour=tmdate->tm_hour - 8;		/* GMT -0800   PST  */
tmdate->tm_gmtoff= -8*3600;
tmdate->tm_zone="PST";
mktime (tmdate);
tmdate->tm_gmtoff= -8*3600;
tmdate->tm_zone="PST";
strftime( (char*) sdate, 200, fmt, tmdate);
printf ("%s\n", sdate);

tmdate=gmtime(&tnum);				/* GMT again */
tmdate->tm_hour=tmdate->tm_hour + 8;		/* GMT +0800   Beijing
*/
tmdate->tm_gmtoff= 8*3600;
tmdate->tm_zone="BST";
mktime (tmdate);
tmdate->tm_gmtoff= 8*3600;
tmdate->tm_zone="BST";
strftime( (char*) sdate, 200, fmt, tmdate);
printf ("%s\n", sdate);

exit(0);
}







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|  Felix Tilley                    |
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