From: Jason Green <news AT jgreen4 DOT fsnet DOT co DOT uk>
To: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
Cc: djgpp AT delorie DOT com
Subject: Re: strftime: Need Help with Time Offsets
Date: Tue, 26 Dec 2000 23:36:06 +0000
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On Sun, 24 Dec 2000, Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> wrote:

> On Sat, 23 Dec 2000, Jason Green wrote:
> 
> > > But C99 defines about a dozen more conversion specifiers which aren't
> > > supported by DJGPP right now.  It would be nice to add them as well.
> > 
> > I agree, but this all takes time.  If %z is fixed now shouldn't it go
> > in?
> 
> I didn't say it shouldn't.  But fixing %z alone doesn't sound like a big 
> win to me.  

Well I started this by trying to fix one user's problem...  :-/

AFAICT, the good news is that DJGPP is not far from compliant already
(if you conveniently ignore locales).

Apart from support for locales, the missing/changed functionality
seems straight forward to implement.  The only one I really have a
problem with is calculating ISO week numbers.

>  Also, the docs needs to be amended to describe %z.

--- src/libc/ansi/time/strftime.txh.orig  Mon Aug  2 12:28:18 1999
+++ src/libc/ansi/time/strftime.txh     Sun Dec 24 11:01:52 2000
@@ -149,6 +149,10 @@

 The timezone abbreviation (@code{EDT})

+@item %z
+
+The time-zone as hour offset from UTC (@code{-0500})
+
 @item %%

 A percent symbol (@code{%})


> > BTW, if I fill a struct tm with values for 0/Jan/YYYY, then call
> > mktime(), it should be modified to 31/Dec/(YYYY-1), right?  This isn't
> > happening.
> 
> Please post a complete example.

The program below prints:

Mon, 00 Jan 2001

Unless I am mistaken, it should print:

Sun, 31 Dec 2000


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

int main(void)
{
    char str[80];
    struct tm tm;
    
    memset(&tm, 0, sizeof(tm));
    
    tm.tm_mday = 0;
    tm.tm_mon  = 0;
    tm.tm_year = 101;
        
    mktime(&tm);
        
    strftime(str, sizeof(str), "%a, %d %b %Y", &tm);
    puts(str);
    
    return 0;
}