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internal-time-units-per-second

internal-time-units-per-second Constant Variable

Constant Value:

A positive integer , the magnitude of which is implementation-dependent.

Description:

The number of internal time units in one second.

See Also:

get-internal-run-time, get-internal-real-time

Notes:

These units form the basis of the Internal Time format representation.

Expanded Reference: internal-time-units-per-second​

The resolution of internal time​

internal-time-units-per-second is a positive integer indicating how many units of internal time correspond to one second. This determines the resolution of get-internal-real-time and get-internal-run-time.

(integerp internal-time-units-per-second)
=> T

(> internal-time-units-per-second 0)
=> T

internal-time-units-per-second
;; => impl-dependent (e.g., 1000 or 1000000)

Converting internal time to seconds​

Divide an internal time value by this constant to get seconds as a ratio or float.

(let ((start (get-internal-real-time)))
  (sleep 1)
  (let ((elapsed (- (get-internal-real-time) start)))
    (> (float (/ elapsed internal-time-units-per-second)) 0.9)))
;; => T

Converting seconds to internal time units​

Multiply seconds by this constant to get internal time units.

;; 0.5 seconds in internal time units
(> (* 0.5 internal-time-units-per-second) 0)
;; => T

This is a constant, not a function​

Unlike most entries, internal-time-units-per-second is a constant variable, not a function. It does not take arguments.

(constantp 'internal-time-units-per-second)
=> T