我该如何向一个分叉的孩子发出终止Perl信号的信号? [英] How can I signal a forked child to terminate in Perl?

问题描述

如何在分叉的进程之间共享相同的变量?还是我需要在父文件中写入文件，然后在文件存在后读取在子文件中保存的值? $ something似乎从未设置过，因此它只是在睡眠中循环

How can I make the same variable shared between the forked process? Or do I need to write to a file in the parent then read the value saved to the file in the child once the file exists? $something never appears to get set in this so it just loops in the sleep

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";
}

推荐答案

perldoc -f fork :

文件描述符(有时锁定这些描述符)是共享的，而其他所有内容都将被复制.

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

另请参见perldoc perlipc中的与您自己进行双向通信.

更新:再三考虑，您想要这样的东西吗?

Update: On second thought, do you want something like this?

#!/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

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