Hi again,

thank you for your support, in return this code which works for me quite well.

It migth be a good idea to put that in FAQ, but carfully look for key words as I sometimes do not know for which words to look for!

Some remarks to this code
Using the STDIN within the function of the kid I didn't get anything from STDIN. Only this way I was able to get the lines from 'dad'.

Unblocking the read of course forces you to do a sleep or wait (like my function to wait for full minute) otherwise the kid will heat up the pc ;-). It is a bit self adapting to keep the buffer reasonable small..

Not to have so many loops in loops in loops, I first push all readables in @LINES and the treat them.

Who ever wants/will write this FAQ-topic may use/change it.

Thanks for all
Carl

  use IO::Handle;
  my ($readPIPE,$writePIPE, $pid);
  pipe $readPIPE, $writePIPE;
  $writePIPE->autoflush(1);
  $pid = fork;

  if ( !$pid ) {   # child
    close($writePIPE);
    nonBlockingRead( $readPIPE );
    exit;
  } else { # parent
      close($readPIPE);
      my (n,$s) = (0,0);
      while (1) {
        $s = (int(rand( 50 )));
        sleep (int(rand( 50 )));
        print $writePIPE "Dad: line ",++$n," after $s s\n";
      }
  }

sub nonBlockingRead {
    use IO::Select;
    my $PIPE = ( shift );
    my $SEL = IO::Select->new( $PIPE );
    my @LINES = qw ( ini deafault array size );
    IO::Handle->new_from_fd(fileno( $PIPE ),"r")->blocking(0);

    while ( $SEL->exists( $PIPE ) ) {
      ($sleep,$send) = doWait( $sleep, scalar @LINES );
      @LINES = ();
      foreach my $h ( $SEL->can_read(0) ) {
        push @LINES, ( <$h> );
      }
      foreach my $l ( @LINES ) {
        &doSomething( $l );
      }
    }
}

sub doWait {
    my $sec = (shift);
    my $NoL = (shift); #: every whole min
    $sec = ($NoL>20)?($sec/2):(($NoL< 5)?($sec+1):$sec);
    my $m = 60 - (time%60);
    if ( ( $m - $sec/2 ) < $sec ) {
      sleep ($m-0.2);
      return ($sec, 1); # ok full Min
    } else {
      sleep ($sec);
      return ($sec, 0); # default
    }
  }

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In reply to Re^4: forked kid can't read from IO::Select->can_read by Anonymous Monk
in thread forked kid can't read from IO::Select->can_read by Anonymous Monk

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