#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11140461
use warnings;
use Time::HiRes qw( sleep );
use IO::Select;

my $interval = 1; # FIXME for testing
my $pricing = '';
my $sel = IO::Select->new;
my $time = time;
my $loopcount = 0;

while( 1 )
  {
  if( $sel->count )
    {
    for my $fh ( $sel->can_read(0) )
      {
      if( not sysread $fh, $pricing, 16384, length $pricing )
        {
        $sel->remove( $fh );
        # FIXME process data
        print "\nbuffer : $pricing at loop count $loopcount\n";
        $time = time + $interval;
        }
      }
    }
  elsif( time >= $time )
    {
    if( open my $fh, '-|' )
      {
      $sel->add( $fh );
      $pricing = '';
      }
    else
      {
      sleep 0.7; # FIXME fake net::curl delay time
      print "fake data\n";
      exit;
      }
    }
  # hard loop
  print ++$loopcount, "\r";
  }
[download]