Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi,
I am new to fork, In below code parent wait for child to finish its job and then parents:
print "Still Processing...$cmd\n";
I am wondering while child is busy running the command is it possilble to make parent to:
print "Still Processing...$cmd\n"; 
my $pid = fork();
   
    if ($pid == 0)
    {
        `$cmd`;
        if($?)
        {
            print "Error: $cmd\n";
        }
        exit(0);
    }
    else
    {
        print "Still Processing...$cmd\n";
        waitpid($pid, 0)
    }

[download]
Thanks

Replies are listed 'Best First'.
Re: fork running parent and child parallel
by GrandFather (Saint) on Sep 02, 2010 at 09:07 UTC

    Consider:

    use strict;
use warnings;
use POSIX ":sys_wait_h";

my $pid = fork ();

if ($pid == 0) {
    for (1 .. 10) {
        sleep 1;
        print 'c';
    }
} else {
    while (waitpid ($pid, WNOHANG) == 0) {
        print 'p';
        sleep 1;
    }
}

print "\nDone\n";

    [download]

    Prints:

    ppcpcpccpcpcpcpcpcpc
Done
p
Done

    [download]
    True laziness is hard work
[reply]
[d/l]
[select]

Back to Seekers of Perl Wisdom