ref: f53e048d3a57eeee135e2d8aa3cd72b7f3dc2711
dir: /doc/man3/time.h.3/
.TH time.h 3
.SH NAME
time.h - time types
.SH SYNOPSIS
#include <time.h>
The time.h header declares the following functions:
.nf
char asctime(const struct tm *tm);
clock_t clock(void);
char ctime(const time_t *timep);
double difftime(time_t t1, time_t t2);
struct tm *gmtime(const time_t *timep);
struct tm *localtime(const time_t *timep);
time_t mktime(struct tm *tm);
size_t strftime(char *restrict, size_t, const char *restrict,
const struct tm *restrict);
time_t time(time_t *timer);
.fi
.SH DESCRIPTION
The time.h header defines the following macros:
.B NULL
It expands to an implementation-defined null pointer constant,
as defined in stddef.h header.
.B CLOCKS_PER_SEC
A number used to convert the value returned by the
.BR clock ()
function into seconds. The value is an expression with type
clock_t.
The time.h header defines the following types:
.BR clock_t ,
.BR size_t ,
.BR time_t .
The
time.h header declares the
.B tm
structure,
which includes at least the following members:
.nf
int tm_sec Seconds[0,60]
int tm_min Minutes[0,59]
int tm_hour Hour[0,23]
int tm_mday Day of month [1,31]
int tm_mon Month of year [0,11]
int tm_year Years since 1900
int tm_wday Day of week [0,6] (Sunday =0)
int tm_yday Day of year [0,365]
int tm_isdst Daylight Savings flag
.fi
The members of the
.I tm
structure are:
.TP 10
tm_sec
The number of seconds after the minute, normally in the range 0 to 59,
but can be up to 60 to allow for leap seconds.
.TP
tm_min
The number of minutes after the hour, in the range 0 to 59.
.TP
tm_hour
The number of hours past midnight, in the range 0 to 23.
.TP
tm_mday
The day of the month, in the range 1 to 31.
.TP
tm_mon
The number of months since January, in the range 0 to 11.
.TP
tm_year
The number of years since 1900.
.TP
tm_wday
The number of days since Sunday, in the range 0 to 6.
.TP
tm_yday
The number of days since January 1, in the range 0 to 365.
.TP
tm_isdst
A flag that indicates whether daylight saving time is
in effect at the time described.
The value is positive if daylight saving time is in
effect, zero if it is not, and negative if the information is not
available.
.SH STANDARDS
ISO/IEC 9899:1999 Section 7.23.1 Paragraph 1,2,3,4
.SH SEE ALSO
.BR clock (3)
.BR ctime (3)
.BR difftime (3)
.BR strftime (3)
.BR time (3)