daniel:// stenberg://Jun 16

Today I learned that glibc has a broken %s implementation in strftime. It applies the timezone even when we want UTC...

https://github.com/curl/curl/issues/22038

%time{%s} in --write-out returns wrong epoch on non-UTC hosts · Issue #22038 · curl/curl

I did this Summary curl --write-out '%time{%s}' (and %time{%s.%f}) outputs an epoch value that is offset by the local timezone offset from UTC. On a host in Asia/Shanghai (UTC+8), the value is cons...

GitHub
Show threadIain McLarenJun 16
@bagder ah as soon as any of my code touches UTC in any way I just know I’m about to go down a 2-3 day rabbit hole
Show threadMathias HasselmannJun 16

@imclaren Depends on programming language, and within programming language on toolkit, I'd say?

@bagder

Show threadIain McLarenJun 16
@taschenorakel @bagder respectful strong disagree. UTC is like complex concurrency. It’s a bag of hard even with beautiful programming languages.
Show threadMathias HasselmannJun 16

@imclaren UTC itself or conversion from and to local time?

While huge effort is needed to compute the official UTC timestamp, for us mere mortals it's just "Whatever number my NTP server of trust gives me", not?

Biggest issue, as with all wall times: It is not monotonic...

@bagder

Show threadIain McLarenJun 16

@taschenorakel @bagder conversions. Although I’ve never seen live code dealing with utc that doesn’t involve conversions.

Obligatory xkcd: https://xkcd.com/1883/

Supervillain Plan

xkcd
Show threadMathias HasselmannJun 16

@imclaren Yes, but this is local times, not UTC. Local times are complicated.

@bagder

Show threadIain McLaren
@taschenorakel @bagder maybe it’s just me but I have never worked on prod code that didn’t involve conversion to localtime. For me, working with utc means working with localtime
Jun 16 at 10:47amWeb