perl fork

Perl小手

在perl使用fork进行多进程工作时，我现在遇到一个问题，主程序在wait()的时候，只能退出部分子进程，假设fork了2个子进程，只有1个能退出。
子进程在退出的时候，释放系统资源是否必须有一定的限制？比如：关闭文件的句柄，销毁模块的对象等等，我现在主程序不能等待所有的子进程退出，一直就挂在那里。 子进程的代码应该做怎样的检查？？

谢谢！

apile

In parent process,
you need to  capture

$SIG{CHLD} =\&some_handle;

because , the signal "CHLD"  for the  parent,

will cause the parent to  exit...

and I guess your question is that

when the first child process end, it throws a CHLD

signal to the parent, and the parent process

dies by default,

and at this time , the root process (1) will take over

the position of the parent process...

then the second child process end, it throws a CHLD

signal to the root process...and itself becomes a zombie.....

So If you don't wanna this situation happens ,

just add the line I write above to handle the CHLD Signal....

and maybe you will get the right answer...

Sorry, I am not at my office, and I can't type in chinese at

this machine.....

Try it....

Perl小手

$SIG{CHLD}：当子程序中断或退出时，用于通知主程序的信号。

foreach my $taskfile (@taskfile_list) {
        $child_id = fork();
        if ($child_id ==0) {
my $task_processor = new FC_TaskProcessor($Assistant_Var,$common_msg,$mddb_para_hash);
my $result = $task_processor->;task_process($taskfile);
$task_processor = $task_processor->;close();
        exit(0);
        }
        else {
                push @child_pid,$child_id;
        }
}

for(my $i=0;$i<@child_pid;$i++) {
        print "Wait: $child_pid[$i] \n\n";
        waitpid($child_pid[$i],0);
}
exit(0);

FC_TaskProcessor模块中可能有未释放的资源（文件、telnet等句柄）。

目前情况是子程序无法退出，你看我上面的代码是否有问题？

apile

#!/usr/bin/perl
use IO::Socket;
use POSIX 'WNOHANG';
require "/apile/xxx-lib.pl";
use constant TIMEOUT=>;1; #1 minute

open(STDERR,">;/tmp/svr.err" or die "Can't open STDERR: $!";

my $timeout = shift||TIMEOUT;

#signal handler for child die events
$SIG{CHLD}=sub{while(waitpid(-1,WNOHANG)>;0){ }};

#retrive socket form STDIN
die "STDIN is not a socket" unless -S STDIN;

my $listen_socket = IO::Socket->;new_from_fd(\*STDIN,"+<"
   or die "Can't create socket: $!";

while (1){
  $connection = eval{
    local $SIG{ALRM} =sub{die "timeout"};
    alarm($timeout*60);
    return $listen_socket->;accept;
  };
  alarm(0);
  exit 0 unless $connection;

  die "Can't fork: $!" unless defined(my $child = fork());
  if($child == 0){
    $listen_socket->;close;
    interact($connection);
    exit 0;
  }
  $connection->;close;
}

這是我拿來寫Wait Server用的程序碼，從
Network programming with perl中抄出來的..
給你當參考...最要緊得是SIG{CHLD}要讓他不要
使得Parent Process死掉，所以才有上面的語法..
因為Parent一死...Child process的行為就很難
控制了..也許你看到的是Zombie也說不定..