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TM(3) NetBSD Library Functions Manual TM(3)
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Maintained for NetBSD
by Kimmo Suominen.
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tm -- time structure
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.
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
The tm_gmtoff field denotes the offset (in seconds) of the time repre-
sented from UTC, with positive values indicating east of the Prime Merid-
ian. 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).
asctime(3), offtime(3), timeval(3), wcsftime(3)
The tm structure conforms to IEEE Std 1003.1-2008 (``POSIX.1'') with
respect to the described standard structure members.
NetBSD 9.99 April 14, 2011 NetBSD 9.99