Module Time

module Time: sig .. end
A module for representing absolute points in time, independent of time zone.

module Ofday: sig .. end
module Span: sig .. end
module Zone: module type of Zone  with type t = Zone.t
type t = Time_internal.T.t 
A fully qualified point in time, independent of timezone.
val get_sexp_zone : unit -> Zone.t
Sexp conversions use the local timezone by default. This can be overridden by calling set_sexp_zone.
val set_sexp_zone : Zone.t -> unit
include Hashable_binable
include Comparable_binable
include Robustly_comparable
include Floatable
include Pretty_printer.S
include Stringable
The {to,of}_string functions in Time will produce times with time zone indications, but are generous in what they will read in. String/Sexp.t representations without time zone indications are assumed to be in the machine's local zone.

values


Unlike Time_ns, this module purposely omits max_value and min_value: 1. They produce unintuitive corner cases because most people's mental models of time do not include +/- infinity as concrete values 2. In practice, when people ask for these values, it is for questionable uses, e.g., as null values to use in place of explicit options.
val epoch : t
midnight, Jan 1, 1970 in UTC

Basic operations on times

val add : t -> Span.t -> t
add t s adds the span s to time t and returns the resulting time.

NOTE: adding spans as a means of adding days is not accurate, and may run into trouble due to shifts in daylight savings time, float arithmetic issues, and leap seconds. See the comment at the top of Zone.mli for a more complete discussion of some of the issues of time-keeping. For spans that cross date boundaries, use date functions instead.

val sub : t -> Span.t -> t
sub t s subtracts the span s from time t and returns the resulting time. See important note for add.
val diff : t -> t -> Span.t
diff t1 t2 returns time t1 minus time t2.
val abs_diff : t -> t -> Span.t
abs_diff t1 t2 returns the absolute span of time t1 minus time t2.

Comparisons

val is_earlier : t -> than:t -> bool
is_earlier and is_later are like using <., but easier to read.
val is_later : t -> than:t -> bool

Constants


Conversions


All these conversion functions use the current time zone. Unless marked _utc, in which case they use Universal Coordinated Time
val of_date_ofday : Date0.t -> Ofday.t -> zone:Zone.t -> t
val to_date_ofday : t -> zone:Zone.t -> Date0.t * Ofday.t
val to_date : t -> zone:Zone.t -> Date0.t
val to_ofday : t -> zone:Zone.t -> Ofday.t
val of_date_ofday_precise : Date0.t ->
Ofday.t ->
zone:Zone.t ->
[ `Never of t | `Once of t | `Twice of t * t ]
Because timezone offsets change throughout the year (clocks go forward or back) some local times can occur twice or not at all. In the case that they occur twice, this function gives `Twice with both occurrences in order; if they do not occur at all, this function gives `Never with the time at which the local clock skips over the desired time of day.

Note that this is really only intended to work with DST transitions and not unusual or dramatic changes, like the calendar change in 1752 (run "cal 9 1752" in a shell to see). In particular it makes the assumption that midnight of each day is unambiguous.

Most callers should use Time.of_date_ofday rather than this function. In the `Twice and `Never cases, Time.of_date_ofday will return reasonable times for most uses.

val convert : from_tz:Zone.t ->
to_tz:Zone.t -> Date0.t -> Ofday.t -> Date0.t * Ofday.t
val utc_offset : t -> zone:Zone.t -> Span.t

Other string conversions

val to_filename_string : t -> zone:Zone.t -> string
to_filename_string t ~zone converts t to string with format YYYY-MM-DD_HH-MM-SS.mmm which is suitable for using in filenames.
val of_filename_string : string -> zone:Zone.t -> t
of_filename_string s ~zone converts s that has format YYYY-MM-DD_HH-MM-SS.mmm into time.
val to_string_fix_proto : [ `Local | `Utc ] -> t -> string
val of_string_fix_proto : [ `Local | `Utc ] -> string -> t
val to_string_trimmed : t -> zone:Zone.t -> string
Same as to_string_abs, but removes trailing seconds and milliseconds if they are 0
val to_sec_string : t -> zone:Zone.t -> string
Same as to_string_abs, but without milliseconds
val of_localized_string : zone:Zone.t -> string -> t
of_localized_string ~zone str read in the given string assuming that it represents a time in zone and return the appropriate Time.t
val to_string_abs : t -> zone:Zone.t -> string
to_string_abs ~zone t returns a string that represents an absolute time, rather than a local time with an assumed time zone. This string can be round-tripped, even on a machine in a different time zone than the machine that wrote the string.

The string will display the date and of-day of zone together with zone as an offset from UTC.

to_string_abs_trimmed is the same as to_string_abs, but drops trailing seconds and milliseconds if they are 0.

Note that the difference between to_string and to_string_abs is not that one returns an absolute time and one doesn't, but that to_string_abs lets you specify the time zone, while to_string takes it to be the local time zone.

val to_string_abs_trimmed : t -> zone:Zone.t -> string
val of_string_abs : string -> t
of_string_abs s is like of_string, but demands that s indicate the timezone the time is expressed in.
val t_of_sexp_abs : Core_kernel.Std.Sexp.t -> t
t_of_sexp_abs sexp as t_of_sexp, but demands that sexp indicate the timezone the time is expressed in.

Miscellaneous

val now : unit -> t
Returns the current time.
val pause : Span.t -> unit
pause span sleeps for span time.
val interruptible_pause : Span.t -> [ `Ok | `Remaining of Span.t ]
interruptible_pause span sleeps for span time unless interrupted (e.g. by delivery of a signal), in which case the remaining unslept portion of time is returned.
val pause_forever : unit -> Core_kernel.Std.never_returns
pause_forever sleeps indefinitely.
val occurrence : [ `First_after_or_at | `Last_before_or_at ] ->
t -> ofday:Ofday.t -> zone:Zone.t -> t
occurrence side time ~ofday ~zone returns a Time.t that is the occurrence of ofday (in the given zone) that is the latest occurrence (<=) time or the earliest occurrence (>=) time, according to side.

NOTE: If the given time converted to wall clock time in the given zone is equal to ofday then the t returned will be equal to the t given.

val format : t -> string -> string
format t fmt formats the given time according to fmt, which follows the formatting rules given in 'man strftime'. The time is output in the local timezone.

      %Y - year (4 digits)
      %y - year (2 digits)
      %m - month
      %d - day
      %H - hour
      %M - minute
      %S - second
   

a common choice would be: %Y-%m-%d %H:%M:%S

val to_epoch : t -> float
to_epoch t returns the number of seconds since Jan 1, 1970 00:00:00 in UTC
val next_multiple : ?can_equal_after:bool ->
base:t -> after:t -> interval:Span.t -> unit -> t
module Stable: sig .. end
val t_of_sexp : Sexplib.Sexp.t -> t
val sexp_of_t : t -> Sexplib.Sexp.t
val bin_t : t Core_kernel.Std.Bin_prot.Type_class.t
val bin_read_t : t Core_kernel.Std.Bin_prot.Read.reader
val __bin_read_t__ : (int -> t) Core_kernel.Std.Bin_prot.Read.reader
val bin_reader_t : t Core_kernel.Std.Bin_prot.Type_class.reader
val bin_size_t : t Core_kernel.Std.Bin_prot.Size.sizer
val bin_write_t : t Core_kernel.Std.Bin_prot.Write.writer
val bin_writer_t : t Core_kernel.Std.Bin_prot.Type_class.writer

Sexp conversions use the local timezone by default. This can be overridden by calling set_sexp_zone.

The {to,of}_string functions in Time will produce times with time zone indications, but are generous in what they will read in. String/Sexp.t representations without time zone indications are assumed to be in the machine's local zone.

values


Unlike Time_ns, this module purposely omits max_value and min_value: 1. They produce unintuitive corner cases because most people's mental models of time do not include +/- infinity as concrete values 2. In practice, when people ask for these values, it is for questionable uses, e.g., as null values to use in place of explicit options.

midnight, Jan 1, 1970 in UTC

Basic operations on times


add t s adds the span s to time t and returns the resulting time.

NOTE: adding spans as a means of adding days is not accurate, and may run into trouble due to shifts in daylight savings time, float arithmetic issues, and leap seconds. See the comment at the top of Zone.mli for a more complete discussion of some of the issues of time-keeping. For spans that cross date boundaries, use date functions instead.

sub t s subtracts the span s from time t and returns the resulting time. See important note for add.

diff t1 t2 returns time t1 minus time t2.

abs_diff t1 t2 returns the absolute span of time t1 minus time t2.

Comparisons


is_earlier and is_later are like using <., but easier to read.

Constants


Conversions


All these conversion functions use the current time zone. Unless marked _utc, in which case they use Universal Coordinated Time

Because timezone offsets change throughout the year (clocks go forward or back) some local times can occur twice or not at all. In the case that they occur twice, this function gives `Twice with both occurrences in order; if they do not occur at all, this function gives `Never with the time at which the local clock skips over the desired time of day.

Note that this is really only intended to work with DST transitions and not unusual or dramatic changes, like the calendar change in 1752 (run "cal 9 1752" in a shell to see). In particular it makes the assumption that midnight of each day is unambiguous.

Most callers should use Time.of_date_ofday rather than this function. In the `Twice and `Never cases, Time.of_date_ofday will return reasonable times for most uses.

Other string conversions


to_filename_string t ~zone converts t to string with format YYYY-MM-DD_HH-MM-SS.mmm which is suitable for using in filenames.

of_filename_string s ~zone converts s that has format YYYY-MM-DD_HH-MM-SS.mmm into time.

Same as to_string_abs, but removes trailing seconds and milliseconds if they are 0

Same as to_string_abs, but without milliseconds

of_localized_string ~zone str read in the given string assuming that it represents a time in zone and return the appropriate Time.t

to_string_abs ~zone t returns a string that represents an absolute time, rather than a local time with an assumed time zone. This string can be round-tripped, even on a machine in a different time zone than the machine that wrote the string.

The string will display the date and of-day of zone together with zone as an offset from UTC.

to_string_abs_trimmed is the same as to_string_abs, but drops trailing seconds and milliseconds if they are 0.

Note that the difference between to_string and to_string_abs is not that one returns an absolute time and one doesn't, but that to_string_abs lets you specify the time zone, while to_string takes it to be the local time zone.

of_string_abs s is like of_string, but demands that s indicate the timezone the time is expressed in.

t_of_sexp_abs sexp as t_of_sexp, but demands that sexp indicate the timezone the time is expressed in.

Miscellaneous


pause span sleeps for span time.

interruptible_pause span sleeps for span time unless interrupted (e.g. by delivery of a signal), in which case the remaining unslept portion of time is returned.

pause_forever sleeps indefinitely.

occurrence side time ~ofday ~zone returns a Time.t that is the occurrence of ofday (in the given zone) that is the latest occurrence (<=) time or the earliest occurrence (>=) time, according to side.

NOTE: If the given time converted to wall clock time in the given zone is equal to ofday then the t returned will be equal to the t given.

format t fmt formats the given time according to fmt, which follows the formatting rules given in 'man strftime'. The time is output in the local timezone.

      %Y - year (4 digits)
      %y - year (2 digits)
      %m - month
      %d - day
      %H - hour
      %M - minute
      %S - second
   

a common choice would be: %Y-%m-%d %H:%M:%S

to_epoch t returns the number of seconds since Jan 1, 1970 00:00:00 in UTC

default is false

Provides a sexp representation that is independent of the time zone of the machine writing it.