in reply to missing second of time

You could also try "fudging" your way to the next second. 

#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11111868
use warnings;
use Time::HiRes qw( time sleep );

my $fudgefactor = 0.01;

while(1)
  {
  my $nextsecond = int time + 1;
  sleep $nextsecond - time - $fudgefactor;
  1 while time < $nextsecond;
  printf "%.6f\n", time;
  }

[download]

Outputs: 

1579972033.000003
1579972034.000004
1579972035.000004
1579972036.000004
1579972037.000004
1579972038.000005
1579972039.000003
1579972040.000004
1579972041.000004
1579972042.000003
1579972043.000003
1579972044.000004
1579972045.000003
1579972046.000005
1579972047.000003

[download]

Looks fairly consistent :)

Replies are listed 'Best First'.
Re^2: missing second of time
by stevieb (Canon) on Jan 25, 2020 at 17:41 UTC

    Nice. Here's a way using select(), so that there's no need for non-core modules (ie. Time::Hires):

    use strict;
use warnings;

my $fudgefactor = 0.01;

while (1) {
  my $nextsecond = int time + 1;
  select(undef, undef, undef, $nextsecond - time - $fudgefactor);
  1 while time < $nextsecond;
  printf "%.6f\n", time;
}

    [download]

    Output:

    1579973997.000000
1579973998.000000
1579973999.000000
1579974000.000000
1579974001.000000
^C

    [download]
[reply]
[d/l]
[select]

      Time::HiRes is core Perl, as much as strict.

      $ corelist Time::HiRes

Data for 2020-01-20
Time::HiRes was first released with perl v5.7.3

      [download]

      Dave

[reply]
[d/l]

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