multithreading - 线程中的 Perl getstore

Question

在以下脚本中:

use strict;
use warnings;
use LWP::Simple;
use threads;
threads->create(sub { 
    my $url = "http://www.example.com/logo.jpg"; 
    my $file = "/var/www/html/logo.jpg"; 
    getstore($url, $file);
    threads->detach();
});

当我启动它时，它不会保存图像，但如果我不在线程中启动相同的代码，它就会工作，为什么？

Answer 1

因为“分离”并没有达到您的预期。当程序退出时，分离的线程将终止。 From the docs...

$thr->detach()

Makes the thread unjoinable, and causes any eventual return value to be discarded. When the program exits, any detached threads that are still running are silently terminated.

您应该收到这样的消息。

Perl exited with active threads:
    1 running and unjoined
    0 finished and unjoined
    0 running and detached

您应该等到程序结束时所有线程都完成，而不是分离。

for my $thread (threads->list(threads::running)) {
    $thread->join;
}

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如果您只想发出并行 HTTP 请求，则不需要线程。 LWP::Parallel可能会更有效率。