multithreading - Not all threads finishing, maybe due to not locking STDOUT -

i experimenting threads in perl. following code creates n threads , assigns same function them (which should execute in parallel).

twist: function prints something. means can't in parallel. fine since starting things them not threads seem finish. suppose due fact haven't locked std out , why conficts occur. may not reason. in case different ammount of threads not finishing each time.

if correct, how can lock stdout (i error when try use lock function) ?

if wrong, why threads not finishing , how can fix ?

the code:

use strict; use threads ('yield',                  'stack_size' => 64*4096,                  'exit' => 'threads_only',                  'stringify'); use threads::shared;   sub printtestmessage() {     print "hello world\n"; }  @t; push @t, threads->new(\&printtestmessage) 1..10; 

i 10 times hello world, after program finishes different output:

perl exited active threads:     1 running , unjoined     9 finished , unjoined     0 running , detached perl exited active threads:     8 running , unjoined     2 finished , unjoined     0 running , detached perl exited active threads:     5 running , unjoined     5 finished , unjoined     0 running , detached 

why haven't threads finished ? ( unjoined because never join them in code expected)

you have join threads, otherwise main thread (as in example) finish before child threads,

$_->join @t; 

from perldoc threads,

$thr->join()

this wait corresponding thread complete execution. when thread finishes, ->join() return return value(s) of entry point function.