AnyEvent::Fork failed with sysread filehadle

[Genban Tade]

Hi,
I'm try to use AnyEvent::Fork and here is my test code:

my $cv = AE::cv;
my $l = [];

AnyEvent::Fork
   ->new
   ->eval ('
        # compile a helper function for later use
        sub run {
            my $fh = shift;
            sleep 10;
        }
     ')
    ->run ("run", sub {
        my ($fh) = @_;
        my $n = sysread $fh, my $dummy, 1;   # doesn't block here
        print $!;
        print "$dummy, here\n";
        $cv->send;
         }
   );

my $stderr = $cv->recv;

wish to use sysread to detect the child process exit, expect it will block
until the child exit, but it  not, and directly return undef and $! is
     "Resource temporarily unavailable"

I also tried replace sysread with a AE io watcher:

        my $rw; $rw = AE::io $fh, 0, sub {
            print "parent here\n";
            print <$fh> . "\n";   # wierd, this line is required
           undef $rw;
           $cv->send;
        };
       $l->[0] = $rw;

this works, and print:
parent here

the wierd thing is, the line "print <$fh> . "\n";" must exist, otherwise,
it'll blocked and never print anything.

can you figure out where's wrong in my code?


Regards,

tadegenban
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