This site is a static rendering of the Trac instance that was used by R7RS-WG1 for its work on R7RS-small (PDF), which was ratified in 2013. For more information, see Home.

Source for wiki TimeCowan version 13

author

cowan

comment

ipnr

98.14.172.204

name

TimeCowan

readonly

text

== Time ==

`(current-posix-second)`

Returns an rational number representing the current second of the Posix epoch, which began on 00:00:00 on 1 January 1970, Coordinated Universal Time but excludes all leap seconds.  Implementations SHOULD return a value that:

 * Is as accurate as reasonably achievable.
 * Provides at least 1-second precision.
 * Provides a range of at least 2^31^ seconds before and after the epoch.

If the implementation cannot provide the time when `current-posix-seconds` is called (either temporarily or permanently), it MUST return `#f`.

Assuming the number of leap seconds between 1972 and 2011 was typical (not necessarily a safe assumption), there is about a 1 in 10^-8^ probability that a computation of elapsed time made by calling this procedure twice will be off by 1.

== Date and Time Arithmetic (WG2) ==

See TimeAdvancedCowan.

== Time Durations and Periods (WG2) ==

See TimePeriodsCowan.

== Time formatting (WG2) ==

See TimeFormattingCowan.

time

2010-11-29 11:38:10