#include <time.h> size_tstrftime(char *s, size_t max, const char *format, const struct tm *tm){	char *s₀, *e, *f, c;	int i;	Tm t; 	memset(&t, 0, sizeof(t));	t.sec = tm->tm_sec;	t.min = tm->tm_min;	t.hour = tm->tm_hour;	t.mday = tm->tm_mday;	t.mon = tm->tm_mon;	t.year = tm->tm_year;	t.wday = tm->tm_wday;	t.yday = tm->tm_yday;	t.tzoff = 0;	t.tz = tzload(tm->tm_zone);	/* ... = tm->tm_isdst; */ /* FIXME */ 	*s = 0;	s₀ = s;	e = s+max;	for(i = 0; format[i]; i++){		if((c = format[i]) == '%'){			c = format[i+1];			f = nil;			switch(c){			case 'Y': f = "YYYY"; break;			case 'm': f = "MM"; break;			case 'd': f = "DD"; break;			case 'H': f = "hh"; break;			case 'M': f = "mm"; break;			case 'S': f = "ss"; break;			/* FIXME - more formatting */			case '%': break;			default: s = seprint(s, e, "%%"); break;			}			i++;			if(f != nil){				s = seprint(s, e, "%τ", tmfmt(&t, f));				continue;			}		}		s = seprint(s, e, "%c", c);	} 	return s-s₀;}