fig18_02.pl

PERL语言资料 可以用于PERL程序设计

#!/usr/bin/perl
# Fig. 18.2: fig18_02.pl
# Demonstrates the wait function.

use warnings;
use strict;

my ( $pid, $pid2 );
$| = 1;

if ( ( $pid = fork() ) && ( $pid2 = fork() ) ) {
   print( "I have to wait for my kids.\n" );
   my $straggler = wait();
   print( "Finally $straggler finished, now I can go.\n" );
}
elsif ( $pid && defined( $pid2 ) ) {
   sleep( 2 );
   print( "Kid 2: So is mine...\n" );
   sleep( 4 );
   exit();
}
elsif ( defined( $pid ) ) {
   sleep( 1 );
   print( "Kid 1: My parent is patient...\n" );
   sleep( 2 );
}
else {
   die( "Forking problems: " );
}



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