NAME
tm —
time structure
SYNOPSIS
#include <time.h>
DESCRIPTION
The
<time.h> header defines the
tm structure that contains calendar dates and time
broken down into components. The following standards-compliant fields are
present:
Type |
Field |
Represents |
Range |
int |
tm_sec |
Seconds |
[0, 61] |
int |
tm_min |
Minutes |
[0, 59] |
int |
tm_hour |
Hours since midnight |
[0, 23] |
int |
tm_mday |
Day of the month |
[1, 31] |
int |
tm_mon |
Months since January |
[0, 11] |
int |
tm_year |
Years since 1900 |
|
int |
tm_wday |
Days since Sunday |
[0, 6] |
int |
tm_yday |
Days since January 1 |
[0, 365] |
int |
tm_isdt |
Positive if daylight savings |
>= 0 |
The
tm structure is used by various common library
routines such as
mktime(3),
localtime(3), and
strptime(3). All fields
described above are defined in the
IEEE Std 1003.1-2008
(“POSIX.1”) standard.
NetBSD Extensions
In addition, the following NetBSD-specific fields are available:
Type |
Field |
Represents |
int |
tm_gmtoff |
Offset from UTC in seconds |
__aconst char |
tm_zone |
Timezone abbreviation |
The
tm_zone and
tm_gmtoff fields
exist, and are filled in by applicable library routines, only if arrangements
to do so were made when the library containing these functions was created.
There is no guarantee that these fields will continue to exist in this form in
future releases of
NetBSD.
The
tm_gmtoff field denotes the offset (in seconds) of the
time represented from UTC, with positive values indicating east of the Prime
Meridian. The
tm_zone field will become invalid and
point to freed storage if the corresponding
struct tm
was returned by
localtime_rz(3) and the
const timezone_t tz argument has
been freed by
tzfree(3).
SEE ALSO
asctime(3),
offtime(3),
timeval(3),
wcsftime(3)
STANDARDS
The
tm structure conforms to
IEEE Std
1003.1-2008 (“POSIX.1”) with respect to the described
standard structure members.