perl与线程共享文件句柄

Question

我在网上找到了下面的代码，看起来程序控制循环的方式是检查共享变量$ TERM是否为0。我可以在线程之间共享文件句柄，每个线程处理文件的一行，并在文件到达最后一行时结束循环吗？

#!/usr/bin/perl 

use strict; 
use warnings; 

use threads 1.39; 
use threads::shared; 
use Thread::Queue; 

### Global Variables ### 

# Maximum working threads 
my $MAX_THREADS = 10; 

# Flag to inform all threads that application is terminating 
my $TERM :shared = 0; 

# Threads add their ID to this queue when they are ready for work 
# Also, when app terminates a -1 is added to this queue 
my $IDLE_QUEUE = Thread::Queue->new(); 


### Signal Handling ### 

# Gracefully terminate application on ^C or command line 'kill' 
$SIG{'INT'} = $SIG{'TERM'} = 
    sub { 
     print(">>> Terminating <<<\n"); 
     $TERM = 1; 
     # Add -1 to head of idle queue to signal termination 
     $IDLE_QUEUE->insert(0, -1); 
    }; 


### Main Processing Section ### 
MAIN: 
{ 
    ### INITIALIZE ### 

    # Thread work queues referenced by thread ID 
    my %work_queues; 

    # Create the thread pool 
    for (1..$MAX_THREADS) { 
     # Create a work queue for a thread 
     my $work_q = Thread::Queue->new(); 

     # Create the thread, and give it the work queue 
     my $thr = threads->create('worker', $work_q); 

     # Remember the thread's work queue 
     $work_queues{$thr->tid()} = $work_q; 
    } 


    ### DO WORK ### 

    # Manage the thread pool until signalled to terminate 
    while (! $TERM) { 
     # Wait for an available thread 
     my $tid = $IDLE_QUEUE->dequeue(); 

     # Check for termination condition 
     last if ($tid < 0); 

     # Give the thread some work to do 
     my $work = 5 + int(rand(10)); 
     $work_queues{$tid}->enqueue($work); 
    } 


    ### CLEANING UP ### 

    # Signal all threads that there is no more work 
    $work_queues{$_}->enqueue(-1) foreach keys(%work_queues); 

    # Wait for all the threads to finish 
    $_->join() foreach threads->list(); 
} 

print("Done\n"); 
exit(0); 


### Thread Entry Point Subroutines ### 

# A worker thread 
sub worker 
{ 
    my ($work_q) = @_; 

    # This thread's ID 
    my $tid = threads->tid(); 

    # Work loop 
    do { 
     # Indicate that were are ready to do work 
     printf("Idle  -> %2d\n", $tid); 
     $IDLE_QUEUE->enqueue($tid); 

     # Wait for work from the queue 
     my $work = $work_q->dequeue(); 

     # If no more work, exit 
     last if ($work < 0); 

     # Do some work while monitoring $TERM 
     printf("   %2d <- Working\n", $tid); 
     while (($work > 0) && ! $TERM) { 
      $work -= sleep($work); 
     } 

     # Loop back to idle state if not told to terminate 
    } while (! $TERM); 

    # All done 
    printf("Finished -> %2d\n", $tid); 
} 

Answer 1

我可以分享线程

当文件到达最后一行每个线程处理文件和循环的一行结束第

之间的文件句柄？

是的。只需将文件中的行代替数字提供给工作线程。

顺便说一句，你不需要11个队列来做到这一点。你只需要一个：

#!/usr/bin/perl 

use strict; 
use warnings; 

use threads 1.39; 
use threads::shared; 
use Thread::Queue qw(); 

# Maximum working threads 
my $NUM_WORKERS = 10; 

# Flag to inform all threads that application is terminating 
my $TERM :shared = 0; 

my $request_q = Thread::Queue->new(); 

$SIG{INT} = $SIG{TERM} = \&signal_handler; 

exit(main()); 

sub signal_handler { 
    print(">>> Terminating <<<\n"); 
    $TERM = 1; 
}  

sub main { 
    my @threads; 
    push @threads, threads->create(\&worker) 
     for 1..$NUM_WORKERS; 

    while (!$TERM && defined(my $job = <>)) { 
     chomp($job); 
     $request_q->enqueue($job); 
    } 

    # Signal to threads that there is no more work. 
    $q->enqueue(undef) for 1..$NUM_WORKERS; 

    # Wait for all the threads to finish. 
    $_->join() for @threads; 

    print("Done\n"); 
    return 0; 
} 

sub worker { 
    my $tid = threads->tid(); 

    while (!$TERM && defined(my $job = $request_q->dequeue())) { 
     printf("   %2d <- Working\n", $tid); 

     # Do something with $job. 
     sleep(1+rand(3)); 
    } 

    printf("Finished -> %2d\n", $tid); 
}