Beefy Boxes and Bandwidth Generously Provided by pair Networks
Welcome to the Monastery
 
PerlMonks  

Re: using fork

by moritz (Cardinal)
on Oct 14, 2013 at 16:27 UTC ( #1058197=note: print w/replies, xml ) Need Help??


in reply to using fork

What jethro said: Only fork if you need to do something in both processes.

If that's the case, here is a working example:

#!/usr/bin/env perl use 5.014; use strict; use warnings; my $pid = fork; if (!defined $pid) { die "Cannot fork: $!"; } elsif ($pid == 0) { # client process say "Client starting..."; sleep 10; # do something useful instead! say "Client terminating"; exit 0; } else { # parent process say "Parent process, waiting for child..."; # do something useful here! waitpid $pid, 0; } say "Parent process after child has finished";

One thing to note is that fork returns undef on failure, and undef == 0 compares as true, so your error handling wouldn't work. To easily test the error case, start a new bash and set ulimit -u $number_of_allowed_processes, then start the perl script.

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1058197]
help
Chatterbox?
[Corion]: erix: I'm not sure if it really is MySQL - maybe MS SQL also has LIMIT 0
[erix]: it has TOP, IIRC
[Corion]: erix: Ah. I use where 1 = 0 for queries where I only am interested in the structure ;)
[erix]: 1=0 is as short as TOP :)
[erix]: "code of someone that died" -- kinda nice if your code stops working too
[erix]: hard to implement, hmm

How do I use this? | Other CB clients
Other Users?
Others exploiting the Monastery: (10)
As of 2017-01-23 09:32 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    Do you watch meteor showers?




    Results (192 votes). Check out past polls.