Time::Piece - phpMan

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NAME SYNOPSIS DESCRIPTION USAGE CAVEATS AUTHOR COPYRIGHT AND LICENSE SEE ALSO BUGS
NAME
    Time::Piece - Object Oriented time objects

SYNOPSIS
        use Time::Piece;

        my $t = localtime;
        print "Time is $t\n";
        print "Year is ", $t->year, "\n";

DESCRIPTION
    This module replaces the standard "localtime" and "gmtime" functions
    with implementations that return objects. It does so in a backwards
    compatible manner, so that using localtime/gmtime in the way documented
    in perlfunc will still return what you expect.

    The module actually implements most of an interface described by Larry
    Wall on the perl5-porters mailing list here:
    <https://www.nntp.perl.org/group/perl.perl5.porters/2000/01/msg5283.html
    >

USAGE
    After importing this module, when you use localtime or gmtime in a
    scalar context, rather than getting an ordinary scalar string
    representing the date and time, you get a Time::Piece object, whose
    stringification happens to produce the same effect as the localtime and
    gmtime functions. There is also a new() constructor provided, which is
    the same as localtime(), except when passed a Time::Piece object, in
    which case it's a copy constructor. The following methods are available
    on the object:

        $t->sec                 # also available as $t->second
        $t->min                 # also available as $t->minute
        $t->hour                # 24 hour
        $t->mday                # also available as $t->day_of_month
        $t->mon                 # 1 = January
        $t->_mon                # 0 = January
        $t->monname             # Feb
        $t->month               # same as $t->monname
        $t->fullmonth           # February
        $t->year                # based at 0 (year 0 AD is, of course 1 BC)
        $t->_year               # year minus 1900
        $t->yy                  # 2 digit year
        $t->wday                # 1 = Sunday
        $t->_wday               # 0 = Sunday
        $t->day_of_week         # 0 = Sunday
        $t->wdayname            # Tue
        $t->day                 # same as wdayname
        $t->fullday             # Tuesday
        $t->yday                # also available as $t->day_of_year, 0 = Jan 01
        $t->isdst               # also available as $t->daylight_savings

        $t->hms                 # 12:34:56
        $t->hms(".")            # 12.34.56
        $t->time                # same as $t->hms

        $t->ymd                 # 2000-02-29
        $t->date                # same as $t->ymd
        $t->mdy                 # 02-29-2000
        $t->mdy("/")            # 02/29/2000
        $t->dmy                 # 29-02-2000
        $t->dmy(".")            # 29.02.2000
        $t->datetime            # 2000-02-29T12:34:56 (ISO 8601)
        $t->cdate               # Tue Feb 29 12:34:56 2000
        "$t"                    # same as $t->cdate

        $t->epoch               # seconds since the epoch
        $t->tzoffset            # timezone offset in a Time::Seconds object

        $t->julian_day          # number of days since Julian period began
        $t->mjd                 # modified Julian date (JD-2400000.5 days)

        $t->week                # week number (ISO 8601)

        $t->is_leap_year        # true if it's a leap year
        $t->month_last_day      # 28-31

        $t->time_separator($s)  # set the default separator (default ":")
        $t->date_separator($s)  # set the default separator (default "-")
        $t->day_list(@days)     # set the default weekdays
        $t->mon_list(@days)     # set the default months

        $t->strftime(FORMAT)    # same as POSIX::strftime (without the overhead
                                # of the full POSIX extension)
        $t->strftime()          # "Tue, 29 Feb 2000 12:34:56 GMT"

        Time::Piece->strptime(STRING, FORMAT)
                                # see strptime man page. Creates a new
                                # Time::Piece object

    Note that "localtime" and "gmtime" are not listed above. If called as
    methods on a Time::Piece object, they act as constructors, returning a
    new Time::Piece object for the current time. In other words: they're not
    useful as methods.

  Local Locales
    Both wdayname (day) and monname (month) allow passing in a list to use
    to index the name of the days against. This can be useful if you need to
    implement some form of localisation without actually installing or using
    locales. Note that this is a global override and will affect all
    Time::Piece instances.

      my @days = qw( Dimanche Lundi Merdi Mercredi Jeudi Vendredi Samedi );

      my $french_day = localtime->day(@days);

    These settings can be overridden globally too:

      Time::Piece::day_list(@days);

    Or for months:

      Time::Piece::mon_list(@months);

    And locally for months:

      print localtime->month(@months);

    Or to populate with your current system locale call:
    Time::Piece->use_locale();

  Date Calculations
    It's possible to use simple addition and subtraction of objects:

        use Time::Seconds;

        my $seconds = $t1 - $t2;
        $t1 += ONE_DAY; # add 1 day (constant from Time::Seconds)

    The following are valid ($t1 and $t2 are Time::Piece objects):

        $t1 - $t2; # returns Time::Seconds object
        $t1 - 42; # returns Time::Piece object
        $t1 + 533; # returns Time::Piece object

    However adding a Time::Piece object to another Time::Piece object will
    cause a runtime error.

    Note that the first of the above returns a Time::Seconds object, so
    while examining the object will print the number of seconds (because of
    the overloading), you can also get the number of minutes, hours, days,
    weeks and years in that delta, using the Time::Seconds API.

    In addition to adding seconds, there are two APIs for adding months and
    years:

        $t = $t->add_months(6);
        $t = $t->add_years(5);

    The months and years can be negative for subtractions. Note that there
    is some "strange" behaviour when adding and subtracting months at the
    ends of months. Generally when the resulting month is shorter than the
    starting month then the number of overlap days is added. For example
    subtracting a month from 2008-03-31 will not result in 2008-02-31 as
    this is an impossible date. Instead you will get 2008-03-02. This
    appears to be consistent with other date manipulation tools.

  Truncation
    Calling the "truncate" method returns a copy of the object but with the
    time truncated to the start of the supplied unit.

        $t = $t->truncate(to => 'day');

    This example will set the time to midnight on the same date which $t had
    previously. Allowed values for the "to" parameter are: "year",
    "quarter", "month", "day", "hour", "minute" and "second".

  Date Comparisons
    Date comparisons are also possible, using the full suite of "<", ">",
    "<=", ">=", "<=>", "==" and "!=".

  Date Parsing
    Time::Piece has a built-in strptime() function (from FreeBSD), allowing
    you incredibly flexible date parsing routines. For example:

      my $t = Time::Piece->strptime("Sunday 3rd Nov, 1943",
                                    "%A %drd %b, %Y");

      print $t->strftime("%a, %d %b %Y");

    Outputs:

      Wed, 03 Nov 1943

    (see, it's even smart enough to fix my obvious date bug)

    For more information see "man strptime", which should be on all unix
    systems.

    Alternatively look here:
    <http://www.unix.com/man-page/FreeBSD/3/strftime/>

   CAVEAT %A, %a, %B, %b, and friends
    Time::Piece::strptime by default can only parse American English date
    names. Meanwhile, Time::Piece->strftime() will return date names that
    use the current configured system locale. This means dates returned by
    strftime might not be able to be parsed by strptime. This is the default
    behavior and can be overridden by calling Time::Piece->use_locale().
    This builds a list of the current locale's day and month names which
    strptime will use to parse with. Note this is a global override and will
    affect all Time::Piece instances.

    For instance with a German locale:

        localtime->day_list();

    Returns

        ( 'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat' )

    While:

        Time::Piece->use_locale();
        localtime->day_list();

    Returns

        ( 'So', 'Mo', 'Di', 'Mi', 'Do', 'Fr', 'Sa' )

  YYYY-MM-DDThh:mm:ss
    The ISO 8601 standard defines the date format to be YYYY-MM-DD, and the
    time format to be hh:mm:ss (24 hour clock), and if combined, they should
    be concatenated with date first and with a capital 'T' in front of the
    time.

  Week Number
    The *week number* may be an unknown concept to some readers. The ISO
    8601 standard defines that weeks begin on a Monday and week 1 of the
    year is the week that includes both January 4th and the first Thursday
    of the year. In other words, if the first Monday of January is the 2nd,
    3rd, or 4th, the preceding days of the January are part of the last week
    of the preceding year. Week numbers range from 1 to 53.

  Global Overriding
    Finally, it's possible to override localtime and gmtime everywhere, by
    including the ':override' tag in the import list:

        use Time::Piece ':override';

CAVEATS
  Setting $ENV{TZ} in Threads on Win32
    Note that when using perl in the default build configuration on Win32
    (specifically, when perl is built with PERL_IMPLICIT_SYS), each perl
    interpreter maintains its own copy of the environment and only the main
    interpreter will update the process environment seen by strftime.

    Therefore, if you make changes to $ENV{TZ} from inside a thread other
    than the main thread then those changes will not be seen by strftime if
    you subsequently call that with the %Z formatting code. You must change
    $ENV{TZ} in the main thread to have the desired effect in this case (and
    you must also call _tzset() in the main thread to register the
    environment change).

    Furthermore, remember that this caveat also applies to fork(), which is
    emulated by threads on Win32.

  Use of epoch seconds
    This module internally uses the epoch seconds system that is provided
    via the perl "time()" function and supported by "gmtime()" and
    "localtime()".

    If your perl does not support times larger than "2^31" seconds then this
    module is likely to fail at processing dates beyond the year 2038. There
    are moves afoot to fix that in perl. Alternatively use 64 bit perl. Or
    if none of those are options, use the DateTime module which has support
    for years well into the future and past.

    Also, the internal representation of Time::Piece->strftime deviates from
    the standard POSIX implementation in that is uses the epoch (instead of
    separate year, month, day parts). This change was added in version 1.30.
    If you must have a more traditional strftime (which will normally never
    calculate day light saving times correctly), you can pass the date parts
    from Time::Piece into the strftime function provided by the POSIX module
    (see strftime in POSIX ).

AUTHOR
    Matt Sergeant, matt AT sergeant.org Jarkko Hietaniemi, jhi AT iki.fi (while
    creating Time::Piece for core perl)

COPYRIGHT AND LICENSE
    Copyright 2001, Larry Wall.

    This module is free software, you may distribute it under the same terms
    as Perl.

SEE ALSO
    The excellent Calendar FAQ at
    <http://www.tondering.dk/claus/calendar.html>

BUGS
    The test harness leaves much to be desired. Patches welcome.


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