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The code is correct, but confusing with all the 'if not's. See RMGir's reply above for an explanation of what the code does. However, to make it less confusing, here's a fork()ing framework that uses straight ifs that are easier to understand (at least for me):
use strict; if (defined(my $pid=fork()) { if ($pid) { # $pid is not 0, so this is the parent # Let's redirect the user (more extensive code in your example). redirect_user(); } else { # $pid=0, so this is the child my $retval=do_child_code(); exit $retval; } } else { # Oops, fork() returned undef - something is definitely wrong. DieNice("Unable to fork: $!\n"); } sub do_child_code { # Do your time consuming stuff, setting $retval to # a useful number return $retval; }
You could do without the else block calling do_child_code, and have the child just fall through down to the child code, but this way it's a lot easier to understand and maintain.

CU
Robartes-


In reply to Re: Understanding fork by robartes
in thread Understanding fork by neilwatson

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