如何判断分叉的子节点在Perl中终止？

如何在分叉进程之间共享相同的变量？或者,我是否需要写入父文件中的文件,然后在文件存在后读取保存到子文件中的值？ $something似乎永远不会在此设置,所以它只是在睡眠中循环

my $something = -1;
&doit();
sub doit
{

 my $pid = fork();
 if ($pid == 0)
 {
      while ($something == -1)
      {
         print "sleep 1\n";
         sleep 1;
      }
      &function2();
 }
 else
 {
     print "parent start\n";
    sleep 2;
    $something = 1;
    print "parent end: $something\n";
 }
}

sub function2 {
   print "END\n";
}

解决方法

perldoc -f fork：

File descriptors (and sometimes locks on those descriptors) are shared,while everything else is copied.

参见perldoc perlipc中的Bidirectional Communication with Yourself.

更新：第二个想法,你想要这样的东西吗？

#!/usr/bin/perl

use strict;
use warnings;

my $pid = fork;

die "Cannot fork: $!" unless defined $pid;

if ($pid == 0) {
    print "Child start\n";
    my $end;
    local $SIG{HUP} = sub { $end = 1 };

    until ($end) {
        print "Sleep 1\n";
        sleep 1;
    }
    function2();
}
else {
    print "Parent start\n";
    sleep 5;
    kill HUP => $pid;
    waitpid($pid,0);
}

sub function2 {
    print "END\n";
}

输出：

C:\Temp> w
Parent start
Child start
Sleep 1
Sleep 1
Sleep 1
Sleep 1
Sleep 1
END