Unix Epoch and PHP's calendar system
I just saw a commit flying past as a response to PHP bug #50155. While right now it is proper to define the Unix Epoch at "1970-01-01 00:00:00 UTC", UTC wasn't actually defined until 1972. So it would be more correct to define the Unix Epoch as "the number of seconds elapsed since midnight proleptic Coordinated Universal Time (UTC) of January 1, 1970, not counting leap seconds." (from Wikipedia). What the bit "not counting leap seconds" means, I've already explained before in Leap Seconds and What To Do With Them.
Similarly, PHP's internal calendar is the ISO 8601 calendar. This is a modification of the proleptic Gregorian calendar. The Gregorian calendar implements the current set of leap years every 4 years, but not every 100 years, but again every 400 years (to get to an average year length of 365.2425 days). Obviously this calendar is only in use since 1582 (some countries adopted it as late as the 1900s), so using days like 1066-10-14 in the Gregorian calendar makes little sense because that calendar didn't exist back then. Now, PHP's ISO 8601-based calendar even modifies the Gregorian calendar by including the year 0. The Gregorian calendar goes straight from -1 to 1 which is a pain to do proper date calculations with. Therefore the ISO 8601 calendar uses Astronomical year numbering.
Life Line
Two Teal Catching the Sun, on Ice
These two Green-winged teals flew in circuits a few times before deciding that the water nearby had thawed enough. When they did, the sun caught their green tail patches perfectly.
#photography #Birds #BirdPhotography #BirdsOfFediverse #NaturePhotography #wildlife #RSPB #RainhamMarshes #london
Specify whether pitches are lit
Specify leaf types
Survey whether benches have backrests
Survey wheelchair accessibility of outside places
Specify whether kerbs have tactile paving
Determine the heights of kerbs
Specify bicycle parkings covers
Specify parking types
Specify whether public transport stops have tactile paving
Specify whether traffic signals have sound signals
Specify whether traffic signals have a button for pedestrians
Specify whether traffic signals have tactile indications that it's safe to cross
Survey postbox collection times
Survey whether laundries provide self-service
Survey opening hours
Survey housenumbers
Specify motorcycle parking capacities
Specify motorcycle parkings covers
Specify parking access
Survey if places still exist
Specify whether roads have sidewalks
Specify cycleways width
Specify cycleway path surfaces
Add footway path surfaces
Shortlink
This article has a short URL available: https://drck.me/ueapcs-7aw