Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
Why?

Exactly! That's the code in the demo script in the Parallel::ForkManager documentation. It's the example I was running and studying earlier. The PIDs and exit codes are included in the code for didactic reasons.

You'll appreciate my similar demo script based on the same kids-in-line-at-the-pool theme.

use strict; use warnings; use Parallel::ForkManager; $| = 1; my $MAXIMUM_KIDS_IN_POOL = 3; my $MAXIMUM_TIME_IN_POOL = 30; # Seconds my $lifeguard = Parallel::ForkManager->new($MAXIMUM_KIDS_IN_POOL); my @kids = qw( Ann Bob Cal Dan Eve Fay Gus Hal Ike Joe Kim Lee Meg ); $lifeguard->run_on_start( sub { my ($pid, $kid) = @_; print "\nThe lifeguard waves $kid into the pool\n"; } ); $lifeguard->run_on_finish( sub { my ($pid, $exit_code, $kid) = @_; print "\n$kid climbs out of the pool\n"; } ); $lifeguard->run_on_wait( sub { print "."; }, 0.3 ); my $number_of_kids = @kids; print "\nThere are $number_of_kids kids in line at the pool\n\n@kids\n +"; KID_IN_LINE: for my $kid (@kids) { my $pid = $lifeguard->start($kid); next KID_IN_LINE if $pid != 0; srand(); my $time = int(rand($MAXIMUM_TIME_IN_POOL)) + 1; print "\n$kid jumps into the pool\n"; sleep $time; print "\nThe lifeguard orders $kid out of the pool after $time sec +onds\n"; sleep 0.5; $lifeguard->finish(); } print "\nAll the kids have been in the pool\n"; $lifeguard->wait_all_children(); print "\nAll the kids are out of the pool\n"; exit 0;

(As I post this script here, I notice there are vestiges of the original script still in the callback subs; namely, $pid and $exit_code. I could remove them.)

Jim

UPDATE:  And if I'm truly serious about not caring about the PIDs, I could do this instead:

next KID_IN_LINE if $lifeguard->start($kid) != 0;

ANOTHER UPDATE:  More weirdness. This works fine…

$lifeguard->run_on_start( sub { my $kid = pop; print "\nThe lifeguard waves $kid into the pool\n"; } );

…but this blows up with Use of uninitialized value $kid in concatenation (.) or string at Pool.pl line 27

$lifeguard->run_on_finish( sub { my $kid = pop; print "\n$kid climbs out of the pool\n"; } );

No variation of pop()-ing @_ in run_on_finish() works.

YET ANOTHER UPDATE:  OK, this is documented in…ahem…the documentation.


In reply to Re^4: Please Explain the Parallel::ForkManager Idiom my $pid = $pm->start and next; by Jim
in thread Please Explain the Parallel::ForkManager Idiom my $pid = $pm->start and next; by Jim

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • 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! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, 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, 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:
    & &amp;
    < &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.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others drinking their drinks and smoking their pipes about the Monastery: (4)
    As of 2015-07-04 00:45 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (57 votes), past polls