CTIME(3) CTIME(3) NAME ctime, localtime, gmtime, asctime, timezone - convert date and time to ASCII SYNOPSIS #include <time.h> char *ctime(clock) long *clock; struct tm *localtime(clock) long *clock; struct tm *gmtime(clock) long *clock; char *asctime(tm) struct tm *tm; char *timezone(zone, dst) DESCRIPTION Ctime converts a time pointed to by clock such as returned by time(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 Localtime and gmtime return pointers to structures contain- ing the broken-down time. Localtime corrects for the time zone and possible daylight savings time; gmtime converts directly to GMT, which is the time UNIX uses. Asctime con- verts a broken-down time to ASCII and returns a pointer to a 26-character string. struct tm { int tm_sec; seconds (range 0..59) int tm_min; minutes (0..59) int tm_hour; hours (0..23) int tm_mday; day of the month (1..31) int tm_mon; month of the year (0..11) int tm_year; year A.D. - 1900 int tm_wday; day of week (0..6, Sunday = 0) int tm_yday; day of year (0..365) int tm_isdst; zero means normal time, nonzero means daylight saving time }; When local time is called for, the program consults the sys- tem to determine the time zone and whether the standard CTIME(3) CTIME(3) U.S.A. daylight saving time adjustment is appropriate. The peculiarities of this conversion are read from the file which contains lines of the form y0 y1 bmon bday boff emon eday eoff meaning that for years between y0 and y1 inclusive, daylight saving time begins (ends) boff (eoff) days after the first Sunday after the day bmon/bday (emon/eday). Timezone returns the name of the time zone associated with its first argument, which is measured in minutes westward from Greenwich. If the second argument is 0, the standard name is used, otherwise the Daylight Saving version. If the required name does not appear in a table built into the rou- tine, the difference from GMT is produced. Thus, as Afghan- istan is 4:30 ahead of GMT, timezone(-(60*4+30), 0) returns "GMT+4:30". SEE ALSO time(2), timec(3) BUGS The return values point to static data whose content is overwritten by each call.