Well, to use the cond_wait stuff, the parent should lock before creating the child. This will work:

use strict; use warnings;         # hallelujah
use threads; use threads::shared; # threads, oh how I hate

my $lockvar : shared = 0;

my $thrHandle;
{
    lock $lockvar;
    $thrHandle = threads->create( \&exampleSub );
    cond_wait ($lockvar);
    print "parent running\n";
}
$thrHandle->join();

sub exampleSub {
    print "child init\n";
    sleep 2;
    print "child init finished\n";
    {
        lock $lockvar;
        cond_signal($lockvar);
    }
    print "child running\n";
}
[download]

However, that is the hard way. The cond_* functions are very low-level, and for most purposes you should use a higher-level abstraction: e.g., create a queue, and signal by pushing an item onto the queue:

use strict; use warnings;         # hallelujah
use threads; use threads::shared; # threads, oh how I hate
use Thread::Queue;

my $q = Thread::Queue->new;


my $thrHandle = threads->create( \&exampleSub );
$q->dequeue;
print "parent running\n";
$thrHandle->join();

sub exampleSub {
    print "child init\n";
    sleep 2;
    print "child init finished\n";
    $q->enqueue(0);
    print "child running\n";
}
[download]

Dave

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.