threads->kill('TERM');
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Then I made a little more change to you code as:

#/usr/bin/perl 

use strict;
use warnings;
use threads;
use threads::shared;
$SIG{INT} = \&catchCtrlC;
my @thrList;
my $count = 1;
share $count;

my $counter = 3;

while($counter) {
     $counter--;
     my $thrHandle = threads->create(\&thrdfun);
     push @thrList, $thrHandle;    
}

foreach(@thrList){
     $_->join(); 
    }   
    
sub catch_CtrlC {
        foreach(@thrList){
            $_->kill('TERM'); 
        }         
    }

sub thrdfun {    
     print "thrdfun: $count \n";
     $count++;
     while(1){
         ();
     }
     exit;
}
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It doesn't work. Could you tell me why?

Just remember that sub catch_CtrlC {} and SIG{'INT'} = \&catch_CtrlC; must both be included in each thread that you want to SIGINT out of.

#/usr/bin/perl

use strict;
use warnings;
use threads;
use threads::shared;

my @thrList;
my $count = 1;
share $count;

my $counter = 3;

while ($counter) {
    $counter--;
    my $thrHandle = threads->create( \&thrdfun );
    push @thrList, $thrHandle;
}

foreach (@thrList) {
    $_->join();
}

sub thrdfun {

    sub catch_CtrlC {
        $_->kill('TERM');
    }

    $SIG{'INT'} = \&catch_CtrlC;
    print "thrdfun: $count \n";
    $count++;
    while (1) {
        ();
    }
    exit;
}
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OK, I got the point. The thread sig handler should be defined inside the thread body, different from the process signal handler.

What's more, can catch_CtrlC gets parameters? Why below little change, adding a print in catch_CtrlC doesn't print anything(see line print "counter: $counter \n"; )?

#/usr/bin/perl 

use strict;
use warnings;
use threads;
use threads::shared;

my @thrList;
my $count = 1;
share $count;

my $counter = 3;

while($counter) {
     $counter--;
     my $thrHandle = threads->create(\&thrdfun);
     push @thrList, $thrHandle;    
}

foreach(@thrList){
     $_->join(); 
    }    

sub thrdfun {
    sub catch_CtrlC {            
        print "counter: $counter \n";
        $SIG{'INT'} = threads->kill('TERM');
    }
    
    $SIG{INT} = \&catchCtrlC;
     print "thrdfun: $count \n";
     $count++;
     while(1){
         ();
     }
     exit;
}
[download]