Hi codemonks,

just a, maybe boring, question to you. Is this a nice way to use fork and pipe, or should i change it?

The Task is to "ping" to a list of IP addresses, to check as fast as possible is the host alive or not. So i should do it parallel, i think. And I don't like to use for such a small job any external fancy IPC Cpan Module i like to use Perl internals, also for the sake of performance only 4 Child's parallel.

use strict;
use warnings;

my @nums;
my @pids;
my $max      = 4;
my $children = 0;


foreach my $i ( 0 .. 10 ) {
# for all IP's now just 0 to 10
    pipe( READER, WRITE );
    my $pid;

    if ( $children == $max ) {
        $pid = wait();
        $children--;
    }

    if ( defined( $pid = fork() ) ) {
        if ($pid) {
            $children++;
            print "Parent: forked child ($pid)\n";
            push @pids, $pid;
            close(WRITE);
            my $num = <READER>;
            push @nums, ($num);
            close(READER);
            wait;
        }
        else {
            my $calc = 365 * $i; # just a example
# on this place i will call the function, and capture the
# return message
            print WRITE $calc;
            close(WRITE);
            exit;
        }
    }
    else {
        print "Error: failed to fork\n";
        exit;
    }
}

for my $pid (@pids) {
    waitpid $pid, 0;
}

print "Numbers: @nums \n";
# on this place i will check the array of the return values
[download]

This will be my first use of fork, and i use pipe for the return of the values. If there exists other way's, more clean and/or elegant. I would prefer to hear it.

---

---

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.