• Ruby

d = DateTime.strptime(ts, '%s')

• C++

std::time_t d = std::chrono::system_clock::to_time_t(ts);

• C#

var d = DateTimeOffset.FromUnixTimeSeconds(ts).UtcDateTime;

• D

auto d = SysTime(unixTimeToStdTime(ts), UTC());

• Dart

var d = new DateTime.fromMillisecondsSinceEpoch(ts, isUtc: true);

• Erlang

Timestamp = {Seconds div 1000000, Seconds rem 1000000, 0},
calendar:now_to_universal_time(Timestamp).

• Go

d := time.Unix(ts, 0)

• Haskell

d = posixSecondsToUTCTime . secondsToNominalDiffTime . MkFixed $ toInteger ts

• JS

new Date (ts * 1000)

• Java

Date d = new Date(ts * 1000);
SimpleDateFormat f = new SimpleDateFormat();
f.applyPattern("yyyy-MM-dd HH:mm:ss");
String s = f.format(d);

• Java

long ts = currentTimeMillis();
String d = "%tc".formatted(ts);

• Java

Date d = new Date(ts * 1000);

• Java

LocalDateTime d = LocalDateTime.ofEpochSecond(ts, 0, ZoneOffset.UTC);

• Java

Instant d = Instant.ofEpochSecond(ts);

• PHP

$d = DateTime::createFromFormat('U', $ts);

• Pascal

var
  D: TDateTime;
  TS: TTimeStamp;
begin
  D := TimeStampToDateTime(TS);
end.

• Perl

my $d = DateTime->from_epoch(epoch => $ts)->strftime('%F %T');

• Python

d = datetime.date.fromtimestamp(ts)

• Rust

let d = NaiveDateTime::from_timestamp(ts, 0);