tm(3) - NetBSD Manual Pages

TM(3)                   NetBSD Library Functions Manual                  TM(3)


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 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).


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.

NetBSD 9.3                      April 14, 2011                      NetBSD 9.3