use strict;
use warnings;

use Errno qw( EWOULDBLOCK ) ;

my $from_parent;
my $to_child;

my $pid;
my $mesg_parent = "Hello Child!";
my $mesg_child;
my $test;

pipe( $from_parent, $to_child );

if ( $pid = fork() ) {

   # Parent   
   $SIG{ HUP } = sub{ kill( 15 , $pid ); print( "KILLED CHILD!!!\n" ) };
   
   close( $from_parent );
   
   while ( 1 ) {
      
      eval{ $test = syswrite( $to_child, $mesg_parent, length( $mesg_parent ) ); };
      select( undef, undef, undef, .5);
      
      if ( $@ ) {
         
         print( "trapped error when writing to pipe \$to_child_ssl\n" );
         next;
         
      }
      
      if ( defined $test ) {
         
         print( "Sent message \"$mesg_parent\" to child\n" );
         
      }
      
   }

}
else {

   # Child     
   close( $to_child );
      
   while ( 1 ) {
      
      $test = sysread( $from_parent, $mesg_child, 13 );
      select( undef, undef, undef, .5 );
      
      if ( ! defined $test ) {
      
         if ( $! == EWOULDBLOCK ) {
         
            print( "sysread would be blocked by \$from_parent: $!\n" );
            next;
                        
         }
         else {
         
            die ( "Error when trying to read from \$from_parent: $!\n" );
         
         }
         
      }
      
      print( "In child\n" );
      print( $mesg_child . "\n" );
      
      $mesg_child =~ s/Child/Parent/;
      
      print $mesg_child . "\n";
      
   }
   
}