plan9 man page for ctime

CTIME(2)							System Calls Manual							  CTIME(2)

NAME
       ctime, localtime, gmtime, asctime, timezone - convert date and time to ASCII

SYNOPSIS
       #include <u.h>
       #include <libc.h>

       char* ctime(long clock)

       Tm*   localtime(long clock)

       Tm*   gmtime(long clock)

       char* asctime(Tm *tm)

       /env/timezone

DESCRIPTION
       Ctime  converts	a time clock such as returned by time(2) into ASCII (sic) and returns a pointer to a 30-byte string in the following form.
       All the fields have constant width.

	     Wed Aug  5 01:07:47 EST 1973


       Localtime and gmtime return pointers to structures containing the broken-down time.  Localtime corrects for the time zone and possible day-
       light  savings  time;  gmtime  converts	directly  to GMT.  Asctime converts a broken-down time to ASCII and returns a pointer to a 30-byte
       string.

	      typedef
	      struct {
		    int  sec;	     /* seconds (range 0..59) */
		    int  min;	     /* minutes (0..59) */
		    int  hour;	     /* hours (0..23) */
		    int  mday;	     /* day of the month (1..31) */
		    int  mon;	     /* month of the year (0..11) */
		    int  year;	     /* year A.D. - 1900 */
		    int  wday;	     /* day of week (0..6, Sunday = 0) */
		    int  yday;	     /* day of year (0..365) */
		    char zone[4];    /* time zone name */
	      } Tm;

       When local time is first requested, the program consults the timezone environment variable to determine the time zone and converts  accord-
       ingly.  (This variable is set at system boot time by init(8).)  The timezone variable contains the normal time zone name and its difference
       from GMT in seconds followed by an alternate (daylight) time zone name and its difference followed by a newline.  The remainder is  a  list
       of pairs of times (seconds past the start of 1970, in the first time zone) when the alternate time zone applies.  For example:

	      EST -18000 EDT -14400
	       9943200 25664400 41392800 57718800 ...

       Greenwich Mean Time is represented by

	      GMT 0

SOURCE
       /sys/src/libc/9sys

SEE ALSO
       date(1), time(2), init(8)

BUGS
       The return values point to static data whose content is overwritten by each call.
       Daylight Savings Time is ``normal'' in the Southern hemisphere.
       These routines are not equipped to handle non-ASCII text, and are provincial anyway.

																	  CTIME(2)