Common Lisp library to get accurate wall-clock times on multiple platforms

cl-trivial-clock

* cl-trivial-clock

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Common Lisp library to get accurate wall-clock times on multiple platforms

** Overview

CL:GET-UNIVERSAL-TIME is limited to returning whole seconds, but some
platforms can provide more accurate clocks. This library aims to wrap
platform-specific system calls for this purpose and fall back on
CL:GET-UNIVERSAL-TIME on any unsupported platform.

Currently the [[https://man.archlinux.org/man/clock_gettime.2.en][clock_gettime]] call is used (with CLOCK_REALTIME) on all
Unix systems and [[https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimepreciseasfiletime][GetSystemTimePreciseAsFileTime]] on Windows, except for
Windows versions below version 8 where [[https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimeasfiletime][GetSystemTimeAsFileTime]] is
used.

The following software combinations are tested via GitHub actions on
x86-64:

- [[https://sbcl.org/][SBCL]] (Linux, Windows, macOS, OpenBSD, FreeBSD, DragonflyBSD)
- [[https://ccl.clozure.com/][CCL]] (Linux)
- [[https://ecl.common-lisp.dev/][ECL]] (Linux, macOS, OpenBSD, FreeBSD)

** Installation

cl-trivial-clock can be installed via [[https://www.quicklisp.org/][Quicklisp]] from the [[https://ultralisp.org/][Ultralisp]]
distribution:

#+begin_src lisp
  ;; Install the ultralisp distribution if you don't have it already
  (ql-dist:install-dist "http://dist.ultralisp.org/" :prompt nil)
  ;; Load cl-trivial-clock
  (ql:quickload :trivial-clock)
#+end_src

** Usage

The function NOW returns the number of seconds since the unix epoch
and the number of additional nanoseconds as a second value:

#+begin_src lisp
  ;; Get current wall-clock time:
  (trivial-clock:now)
  ;; => 1688533183 (31 bits, #x64A4F8BF)
  ;;    529460903 (29 bits, #x1F8EEEA7)
#+end_src

*** Running tests

- Load the tests via Quicklisp:

#+begin_src lisp
  (ql:quickload :trivial-clock/test)
#+end_src

- Use [[https://asdf.common-lisp.dev/][ASDF]] or [[https://fiveam.common-lisp.dev/][FiveAM]] to run the tests:

#+begin_src lisp
  ;; Using ASDF:
  (asdf:test-system :trivial-clock)
  ;; Using FiveAM directly:
  (fiveam:run! :trivial-clock)
#+end_src

** Legal

- Released under the MIT License
- [[https://developercertificate.org/][Developer Certificate of Origin]]
- [[https://en.wikipedia.org/wiki/File:Al-jazari_elephant_clock.png][Source]] for README photo


cl-trivial-clock

Upstream URL

Author

License

trivial-clock

License:

Authors:

Dependencies:

trivial-clock/*

Dependencies:

trivial-clock/test

Dependencies:

Dependencies (2)

Dependents (1)