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Diffstat (limited to 'static/plan9-4e/man2/ctime.2')
| -rw-r--r-- | static/plan9-4e/man2/ctime.2 | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/static/plan9-4e/man2/ctime.2 b/static/plan9-4e/man2/ctime.2 new file mode 100644 index 00000000..a4e07434 --- /dev/null +++ b/static/plan9-4e/man2/ctime.2 @@ -0,0 +1,129 @@ +.TH CTIME 2 +.SH NAME +ctime, localtime, gmtime, asctime, tm2sec, timezone \- convert date and time +.SH SYNOPSIS +.B #include <u.h> +.br +.B #include <libc.h> +.PP +.ta \w'\fLchar* 'u +.B +char* ctime(long clock) +.PP +.B +Tm* localtime(long clock) +.PP +.B +Tm* gmtime(long clock) +.PP +.B +char* asctime(Tm *tm) +.PP +.B +long tm2sec(Tm *tm) +.PP +.B +/env/timezone +.SH DESCRIPTION +.I Ctime +converts a time +.I clock +such as returned by +.IR time (2) +into +.SM ASCII +(sic) +and returns a pointer to a +30-byte string +in the following form. +All the fields have constant width. +.PP +.B + Wed Aug 5 01:07:47 EST 1973\en\e0 +.PP +.I Localtime +and +.I gmtime +return pointers to structures containing +the broken-down time. +.I Localtime +corrects for the time zone and possible daylight savings time; +.I gmtime +converts directly to GMT. +.I Asctime +converts a broken-down time to +.SM ASCII +and returns a pointer +to a 30-byte string. +.IP +.EX +.ta 6n +\w'char 'u +\w'zone[4]; 'u +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 */ + int tzoff; /* time zone delta from GMT */ +} Tm; +.EE +.PP +.I Tm2sec +converts a broken-down time to +seconds since the start of the epoch. +It ignores +.BR wday , +and assumes the local time zone +if +.B zone +is not +.BR GMT . +.PP +When local time is first requested, +the program consults the +.B timezone +environment variable to determine the time zone and +converts accordingly. +(This variable is set at system boot time by +.IR init (8).) +The +.B 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: +.IP +.EX +EST -18000 EDT -14400 + 9943200 25664400 41392800 57718800 ... +.EE +.PP +Greenwich Mean Time is represented by +.IP +.EX +GMT 0 +.EE +.SH SOURCE +.B /sys/src/libc/9sys +.SH "SEE ALSO" +.IR date (1), +.IR time (2), +.IR init (8) +.SH BUGS +The return values point to static data +whose content is overwritten by each call. +.br +Daylight Savings Time is ``normal'' in the Southern hemisphere. +.br +These routines are not equipped to handle non-\c +.SM ASCII +text, and are provincial anyway. |