CODEWITHSUNDEEP
multithreadingperlio
s0me0ne
s0me0ne

Reputation: 516

How to interrupt an I/O call in a perl thread?

Looks like times of old good alarm() call are over, so how to interrupt blocking read()'s and write()'s made from perl thread (using that brand new 'threads' module) assuming the code making those blocking calls cannot be changed? Actual problem is stucking communication with Modbus device so I've created a simple testcase not to dip you into RS-485 hell:

use threads;
use IO::Handle;
threads->create(sub {
        $io = IO::Handle->new_from_fd(fileno(STDIN), 'r') or die;
        $br = read $io, $buf, 100;
        warn "read: $br";
});
while(1) {threads->yield()};

Here, warn() is never executed unless you hit Ctrl-D on keyboard. Is there any simple solution to timeout that read() call?

Upvotes: 3

Views: 458

Answers (1)

LeoNerd
LeoNerd

Reputation: 8532

Rather than threading (which is ill-supported in Perl at best, and mostly frowned upon), why not try one of the event modules instead? That's the standard solution to concurrency in Perl.

Upvotes: 1

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