package ptime

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POSIX clock
System time zone offset
POSIX clock raw interface
Error handling
Platform support

package ptime

ptime
- Ptime
  - Span
ptime.clock.os
- Ptime_clock

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POSIX time clock.

Ptime_clock provides access to a system POSIX time clock and to the system's current time zone offset.

This time does not increase monotically and is subject to system calendar time adjustments. Use Mtime if you need monotonic wall-clock time to measure time spans.

Consult important information about error handling and platform support.

v0.8.5 - homepage

POSIX clock

val now : unit -> Ptime.t

now () is the current POSIX time, by definition always on the UTC timeline.

raises Sys_error
see error handling.

val period : unit -> Ptime.span option

period () is a positive POSIX time span representing the clock's period (if available).

System time zone offset

val current_tz_offset_s : unit -> Ptime.tz_offset_s option

current_tz_offset_s () is the system's current local time zone offset to UTC in seconds, if known. This is the duration local time - UTC time in seconds.

POSIX clock raw interface

val now_d_ps : unit -> int * int64

now_d_ps () is (d, ps) representing POSIX time occuring at d * 86'400e12 + ps POSIX picoseconds from the epoch 1970-01-01 00:00:00 UTC. ps is in the range [0;86_399_999_999_999_999L].

raises Sys_error
see error handling

val period_d_ps : unit -> (int * int64) option

period_d_ps () is if available Some (d, ps) representing the clock's picosecond period d * 86'400e12 + ps. ps is in the range [0;86_399_999_999_999_999L].

Error handling

The functions now and now_d_ps raise Sys_error whenever they can't determine the current time or that it doesn't fit in Ptime's well-defined range. This exception should only be catched at the toplevel of your program to log it and abort the program. It indicates a serious error condition in the system.

All the other functions, whose functionality is less essential, simply silently return None if they can't determine the information either because it is unavailable or because an error occured.

Platform support

Platforms with a POSIX clock (includes Linux) use clock_gettime with CLOCK_REALTIME.
On Darwin gettimeofday is used.
On Windows GetSystemTime and GetTimeZoneInformation are used.
On JavaScript Date.now () and Date.prototype.getTimezoneOffset are used.