如何在不终止整个程序的情况下立即结束 Perl 线程？

Question

如何在不终止整个程序的情况下立即结束 Perl 线程？

6

当我使用exit或die时，它会终止整个程序。

foreach my $t (threads->list())
{
    $t->exit;
    $count++;
}

Usage: threads->exit(status) at main.pl line 265
Perl exited with active threads:
        9 running and unjoined
        0 finished and unjoined
        0 running and detached

有什么想法吗？

- Saustin

请查看我的评论：https://dev59.com/kGvXa4cB1Zd3GeqPLavH#27690901 - Paolo Rovelli

3个回答

3

如果你想杀死一个线程，你可以使用$thread->kill。如果你想让线程继续运行但不再与父线程相关，可以使用$thread->detach。threads->exit会导致当前线程退出；它不需要一个线程作为调用者。

- hobbs

0

错误信息告诉你$t->exit需要一个参数。尝试给它一个。（perldoc Threads似乎说不需要，但我不知道你使用的是哪个包。）

- Keith Thompson

我正在使用线程。我尝试过了，没有用。我还用die做了这件事。 - Saustin

$t 是一个 Threads 对象吗？尝试打印 ref $t。在 foreach 循环中的表达式真的是 threads->list() 吗，还是 Threads->list()？ - Keith Thompson

那绝对不是问题。 - Saustin

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Zaid · Accepted Answer

要忽略正在执行的线程，返回控制并丢弃它可能输出的任何内容，正确的方法是使用detach，而不是exit。

请参见perldoc perlthrtut - 忽略线程。

perldoc threads 解释了代码为什么退出：

threads->exit()
If needed, a thread can be exited at any time by calling threads->exit(). This will cause the thread to return undef in a scalar context, or the empty list in a list context. When called from the main thread, this behaves the same as exit(0).

可能有一种方法可以实现即时终止（在Windows上对我无效）：

use threads 'exit' => 'threads_only';
This globally overrides the default behavior of calling exit() inside a thread, and effectively causes such calls to behave the same as threads->exit() . In other words, with this setting, calling exit() causes only the thread to terminate. Because of its global effect, this setting should not be used inside modules or the like. The main thread is unaffected by this setting.

文档还提供了另一种方法，使用 set_thread_exit_only 方法（但在 Windows 上对我无效）：

$thr->set_thread_exit_only(boolean)
This can be used to change the exit thread only behavior for a thread after it has been created. With a true argument, exit() will cause only the thread to exit. With a false argument, exit() will terminate the application. The main thread is unaffected by this call.

下面的示例使用一个kill 信号来终止$unwanted线程：

use strict;
use warnings;
use threads;

my $unwanted = threads->create( sub {
                                      local $SIG{KILL} = sub { threads->exit };
                                      sleep 5;
                                      print "Don't print me!\n";
                                    } );

my $valid    = threads->create( sub {
                                      sleep 2;
                                      print "This will print!\n";
                                    } );

$unwanted->kill('KILL')->detach;   # Kills $thr, cleans up

$valid->join;                 # sleep 2, 'This will print!'