CTIME(3C)           UNIX Programmer's Manual            CTIME(3C)

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

SYNOPSIS
     char *ctime (clock)
     long *clock;

     #include <time.h>

     struct tm *localtime (clock)
     long *clock;

     struct tm *gmtime (clock)
     long *clock;

     char *asctime (tm)
     struct tm *tm;

     tzset ( )

     extern long timezone;

     extern daylight;

     extern char *tzname[2];

HP-UX COMPATIBILITY
     Level:    HP-UX/RUN ONLY

     Origin:   System III

DESCRIPTION
     _C_t_i_m_e converts a time pointed to by _c_l_o_c_k such  as  returned
     by  _t_i_m_e(2)  into  ASCII  and  returns  a  pointer  to a 26-
     character string in the following form.  All the fields have
     constant width.

          Sun Sep 16 01:03:52 1973\n\0

     _L_o_c_a_l_t_i_m_e and _g_m_t_i_m_e return pointers to structures  contain-
     ing  the  broken-down time.  _L_o_c_a_l_t_i_m_e corrects for the time
     zone and possible daylight  savings  time;  _g_m_t_i_m_e  converts
     directly  to  GMT,  which is the time the HP-UX system uses.
     _A_s_c_t_i_m_e converts a broken-down time to ASCII and  returns  a
     pointer to a 26-character string.

     The structure declaration from the include file is:

          struct  tm {
                  int  tm_sec;
                  int  tm_min;
                  int  tm_hour;
                  int  tm_mday;
                  int  tm_mon;
                  int  tm_year;
                  int  tm_wday;
                  int  tm_yday;
                  int  tm_isdst;
          };

     These quantities give the time on a 24-hour  clock,  day  of
     month  (1-31),  month  of year (0-11), day of week (Sunday =
     0), year - 1900, day of year (0-365), and  a  flag  that  is
     non-zero if daylight saving time is in effect.

     The external long variable _t_i_m_e_z_o_n_e contains the difference,
     in  seconds,  between  GMT  and local standard time (in EST,
     _t_i_m_e_z_o_n_e is 5*60*60);  the  external  variable  _d_a_y_l_i_g_h_t  is
     non-zero if and only if the standard U.S.A. Daylight Savings
     Time conversion should be applied.  The program knows  about
     the  peculiarities  of  this conversion in 1974 and 1975; if
     necessary, a table for these years can be extended.

     If an environment variable named TZ is present, _a_s_c_t_i_m_e uses
     the  contents  of  the variable to override the default time
     zone.  The value of TZ must  be  a  three-letter  time  zone
     name,  followed  by  a  number  representing  the difference
     between local time and Greenwich time in hours, followed  by
     an optional three-letter name for a daylight time zone.  For
     example, the setting for New Jersey would be  EST5EDT.   The
     effects  of  setting TZ are thus to change the values of the
     external variables _t_i_m_e_z_o_n_e and _d_a_y_l_i_g_h_t; in  addition,  the
     time zone names contained in the external variable

             char *tzname[2] = {"EST", "EDT"};

     are set from the environment variable.  The  function  _t_z_s_e_t
     sets the external variables from TZ; it is called by _a_s_c_t_i_m_e
     and may also be called explicitly by the user.

SEE ALSO
     time(2), getenv(3C), environ(7).

BUGS
     The return values point to  static  data  whose  content  is
     overwritten by each call.