关于理解Perl的fork函数的一个范例
方便理解，Perl的fork函数派生子进程的过程：[*]#!/usr/bin/perl -w
[*]# wangxiaoyu#live.com
[*]use strict;
[*]
[*]defined(my $pid=fork()) or die "Fork process failured:$!\n";
[*]unless($pid)
[*]{
[*] # This is the child process.
[*] system "date";
[*] sleep(3);
[*] print ("Exit child after 3 seconds wait!\n");
[*] exit();
[*]}
[*]# This is the parent process.
[*]waitpid($pid,0);
[*]system "date";
[*]print ("exit parent!\n");
程序执行结果如下：
# perl perl-fork02.pl
Wed Aug4 22:51:38 HKT 2010
Exit child after 3 seconds wait!
Wed Aug4 22:51:41 HKT 2010
exit parent!
#
如果不在父进程中提供waitpid函数的话，父进程会在成功创建子进程后不等待子进程执行完毕，立即执行其余的代码，这样的话执行的结果如下：
# perl perl-fork02.pl
Wed Aug4 22:50:25 HKT 2010
Wed Aug4 22:50:25 HKT 2010
exit parent!
# Exit child after 3 seconds wait!
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