# Module Netdate

    module Netdate: sig .. end

Support for common date/time parsing and formatting. Many routines refer to the epoch, which for Unix is 00:00:00 UTC, January 1, 1970. Timestamps given as "seconds since the epoch" ignore leap seconds.

    type t = {

`` | `year : `int`;` | `(*` | complete year | `*)`
`` | `month : `int`;` | `(*` | 1..12 | `*)`
`` | `day : `int`;` | `(*` | 1..31 | `*)`
`` | `hour : `int`;` | `(*` | 0..23 | `*)`
`` | `minute : `int`;` | `(*` | 0..59 | `*)`
`` | `second : `int`;` | `(*` | 0..60 (60=leapsecond) | `*)`
`` | `nanos : `int`;` | `(*` | nanoseconds, new since Ocamlnet-3.5 | `*)`
`` | `zone : `int`;` | `(*` | in minutes; 60 = UTC+0100 | `*)`
`` | `week_day : `int`;` | `(*` | 0 = sunday; -1 if not given | `*)`

}

    val localzone : int

The offset in minutes for the local time zone from the UTC. This is the zone from the time when the program was started. For long-running programs, it is possible that the zone changes when daylight savings become effective or non-effective.

    val localzone_nodst : int

Returns the offset for the local time zone for the case that daylight savings are not effective.

    val get_localzone : unit -> int

Retrieves the current offset for the local time zone, taking daylight savings into account.

    val create : ?localzone:bool -> ?zone:int -> ?nanos:int -> float -> t

Convert the time (seconds since the epoch) to a date/time record

The `nanos` are added to the float as nanoseconds.

If `zone` is set this zone is taken. Otherwise, if `localzone` is set, the local timezone is used that is valid at the requested time. Otherwise, UTC is used.

Note that `create ~localzone:true t` is different from `create ~zone:(get_localzone()) t` because the latter assumes the timezone that is in effect when the function is called, and not the timezone at the time `t`.

    type localization = {

`` | `full_day_names : `string array`;` | `(*` | Element `k` contains the name of the week day `k` (0=Sunday) | `*)`
`` | `abbr_day_names : `string array`;` | `(*` | Element `k` contains the abbreviated name of the week day `k` (0=Sunday) | `*)`
`` | `parsed_day_names : `string list array`;` | `(*` | Element `k` contains a list of all possible names of the week day `k`. The list includes full and abbreviated names, but can also contain any other allowed name (aliases). The names here are in lowercase characters. | `*)`
`` | `full_month_names : `string array`;` | `(*` | Element `k` contains the name of the month day `k` (0=January) | `*)`
`` | `abbr_month_names : `string array`;` | `(*` | Element `k` contains the abbreviated name of the month day `k` (0=January) | `*)`
`` | `parsed_month_names : `string list array`;` | `(*` | Element `k` contains a list of all possible names of the month `k`. The list includes full and abbreviated names, but can also contain any other allowed name (aliases). The names here are in lowercase characters. | `*)`
`` | `timezone_names : `(string * int * bool) list`;` | `(*` | A list of pairs `(name,offset,isdst)` of timezones. The offset is in minutes. | `*)`
`` | `am_particle : `string`;` | `(*` | A particle for "AM" | `*)`
`` | `pm_particle : `string`;` | `(*` | A particle for "PM" | `*)`
`` | `d_format : `string`;` | `(*` | Format string for date according to the locale | `*)`
`` | `t_format : `string`;` | `(*` | Format string for time according to the locale | `*)`
`` | `d_t_format : `string`;` | `(*` | Format string for date and time according to the locale | `*)`
`` | `t_format_ampm : `string`;` | `(*` | Format string for time, using am and pm, according to the locale | `*)`
`` | `char_encoding : `string`;` | `(*` | The character encoding of this locale | `*)`

}

    type compiled_localization

    val posix_l9n : localization

The standard POSIX localization (English names)

    val l9n_from_locale : string -> localization

Retrieves the localization from the passed locale (use "" for the standard locale). Timezone names are not provided by the locale

This function is not available on Windows (the POSIX localization is always returned).

    val compile_l9n : localization -> compiled_localization

Preprocess the localization data for faster parsing and printing

    val parse : ?localzone:bool ->
           ?zone:int -> ?l9n:compiled_localization -> string -> t

Parse a string and return a date/time record.

The following particles are recognized (by example):

- Date: `1971/06/22`
- Date: `06/22/1971`
- Date: `1971-06-22`
- Date: `22-June-1971`
- Date: `22.06.1971`
- Date: `June 22, 1971`
- Date: `22 June 1971`
- Date (2 digit year): `06/22/71`
- Date (2 digit year): `22.06.71`
- Date (2 digit year): `71-06-22`
- Date (2 digit year): `22-June-71`
- Month names (`June`, `Jun`)
- Weekday names (`Monday`, `Mon`)
- Time: `14:55`
- Time: `14:55:28`
- Time: `14:55:28.6754` (the fractional part is not returned)
- Time may be preceded by `T`
- Time zone: identifiers like `UTC`, `CET`, or `Z`
- Time zone: `+01:00`, `-01:00`, only following time
- Time zone: `+0100`, `-0100`, only following time

Years must have 2 or 4 digits. 2-digit years >= 70 are interpreted as `1900+x`. 2-digit years < 70 are interpreted as `2000+x`. Support for 2-digit years will be removed in a future version of Ocamlnet. (Support for 3-digit years is already removed in Ocamlnet 3.0.)

The names of months and weekdays are recognized that are configured with the `l9n` argument. By default, English names are recognized.

A date must be given. Time, time zones, and weekdays are optional. A missing time is reported as "00:00:00". A missing weekday is reported by setting `week_day=(-1)`. A missing time zone is reported by setting `zone` to the passed default (which is determined from the `zone` and `localzone` arguments as for `create`).

It is not checked whether the parsed numbers make sense (e.g. whether months are between 1 and 12).

Date/time strings as defined in RFC 3339 are supported since Ocamlnet 3.0.

    val since_epoch : t -> float

Convert a date/time record into the time (seconds since the epoch), rounded down to the next integral number.

    val since_epoch_timespec : t -> float * int

Returns the seconds since the epoch as pair `(seconds,nanos)`

    val since_epoch_approx : t -> float

Same, but the nanos are added to the seconds. The precision of floats is not sufficient to represent this precisely, so the result is only an approximation.

    val week_day : t -> int

Returns the week day. If the `week_day` field is (-1) the week day is computed.

    val year_day : t -> int

Returns the year day (range 0 to 365)

    val iso8601_week_pair : t -> int * int

Returns `(week_number, year)` for the ISO-8601 definition of weeks. The week starts with Monday, and has numbers 1-53. A week is considered to be part of the year into which four or more days fall.

    val parse_epoch : ?l9n:compiled_localization ->
           ?localzone:bool -> ?zone:int -> string -> float

Parse a string and return the time (integral seconds since the epoch)

    val parse_epoch_timespec : ?l9n:compiled_localization ->
           ?localzone:bool -> ?zone:int -> string -> float * int

Parse a string and return the time (seconds and nanos since the epoch)

    val parse_epoch_approx : ?l9n:compiled_localization ->
           ?localzone:bool -> ?zone:int -> string -> float

Parse a string and return the time (approximate seconds since the epoch)

    val format_to : ?l9n:compiled_localization ->
           Netchannels.out_obj_channel -> fmt:string -> t -> unit

Format a date/time record according to the format string and outputs the resulting string to the channel.

The format string consists of zero or more conversion specifications and ordinary characters. All ordinary characters are output directly to the channel. A conversion specification consists of the '%' character and one other character.

The conversion specifications are:

- `%A`: full weekday name.
- `%a`: abbreviated weekday name.
- `%B`: full month name.
- `%b`: abbreviated month name.
- `%C`: (year / 100) as an integer; single digits are preceded by a zero.
- `%c`: the preferred date+time representation of `l9n`
- `%D`: equivalent to `"%m/%d/%y"`.
- `%d`: day of the month as an integer (01-31); single digits are preceded by a zero.
- `%e`: day of the month as an integer (1-31).
- `%F`: equivalent to `"%Y-%m-%d"` (ISO 8601)
- `%G`: the year of the week according to the ISO-8601 week definition
- `%g`: same as %G but uses a two-digit year
- `%H`: hour (24-hour clock) as an integer (00-23).
- `%h`: the same as %b.
- `%I`: hour (12-hour clock) as an integer (01-12).
- `%j`: day of the year as an integer (001-366).
- `%k`: hour (24-hour clock) as an integer (0-23); single digits are preceded by a blank.
- `%l`: hour (12-hour clock) as an integer (1-12); single digits are preceded by a blank.
- `%M`: minute as an integer (00-59).
- `%m`: month as an integer (01-12).
- `%n`: a newline.
- `%p`: "AM" or "PM" as defined in `l9n`, in uppercase
- `%P`: "am" or "pm" as defined in `l9n`, in lowercase
- `%R`: equivalent to `"%H:%M"`.
- `%r`: the time in am/pm notation according to `l9n`
- `%S`: second as an integer (00-60). This format accepts a precision argument, e.g. `%.3S` to print the second with three digits after the dot.
- `%s`: number of seconds since the epoch
- `%T`: equivalent to `"%H:%M:%S"`.
- `%t`: a tab.
- `%U`: week number of the year (Sunday as the first day of the week) as an integer (00-53).
- `%u` weekday (Monday as the first day of the week) as an integer (1-7).
- `%V`: week number of the year (ISO-8601 definition, use together with `%G` or `%g`
- `%W`: week number of the year (Monday as the first day of the week) as an integer (00-53).
- `%w`: weekday (Sunday as the first day of the week) as an integer (0-6).
- `%X`: representation of the time according to `l9n`
- `%x`: representation of the date according to `l9n`
- `%Y`: year with century as an integer.
- `%y`: year without century as an integer (00-99).
- `%z`: time zone offset from UTC; a leading plus sign stands for east of UTC, a minus sign for west of UTC, hours and minutes follow with two digits each and no delimiter between them (common form for RFC 822 date headers).
- `%Z`: same as `%z`
- `%:z`: time zone with colon, e.g. +05:00 (new since Ocamlnet 3)
- `%%`: a `%' character.

If `l9n` is not passed, the default is the POSIX localization (English names).

    val format : ?l9n:compiled_localization -> fmt:string -> t -> string

Format a date/time record as a string

    val mk_date : ?localzone:bool -> ?zone:int -> ?nanos:int -> fmt:string -> float -> string

Format the seconds (plus nanos if present) as a string

    val mk_mail_date : ?localzone:bool -> ?zone:int -> float -> string

Convert the time (seconds since the epoch) to a date string that conforms to RFC 1123 (which updates RFC 822).

Example: `"Sun, 06 Nov 1994 08:49:37 -0500"`.

    val mk_usenet_date : ?localzone:bool -> ?zone:int -> float -> string

Convert the time (seconds since the epoch) to a date string that conforms to RFC 1036 (which obsoletes RFC 850).

Example: `"Sunday, 06-Nov-94 08:49:37 -0500"`.

Note that this format has only two digits for the year.

    val mk_internet_date : ?localzone:bool -> ?zone:int -> ?digits:int -> float -> string

Convert the time (seconds since the epoch) to a date string that conforms to RFC 3339. This is the most modern format, and should be used if permitted by the network protocol. Pass in `digits` the number of digits for the fractional part of seconds.

Example: `"1996-12-19T16:39:57.89-08:00"`.