fig18_15.pl

PERL语言资料 可以用于PERL程序设计

#!/usr/bin/perl
# Fig. 18.15: fig18_15.pl
# Sending signals to child processes using kill.

use warnings;
use strict;
use POSIX qw( :signal_h :errno_h :sys_wait_h );

$SIG{ USR1 } = \&user1;
$SIG{ USR2 } = \&user2;
$| = 1;

sub user1 
{
   $SIG{ USR1 } = \&user1;
   print( "I have received SIGUSR1.\n" );
}

sub user2 
{
   $SIG{ USR2 } = \&user2;
   print( "I have received SIGUSR2.\n" );
}

if ( my $pid = fork ) {
   kill( 'USR1', $pid );
   kill( 'USR2', $pid );
   print( "I have just sent two signals.\n" );
   sleep( 2 );
   print( "Now I am going to send a few more.\n" );
   kill( USR2 => $pid );
   kill( USR1 => $pid );
   print( "Parent done.\n" );
}
elsif ( defined( $pid ) ) {
   sleep( 5 );
   print( "Kid done.\n" );
   exit();
}
else {
   print( "Forking error...\n" );
}

wait();


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