Re: Background Process

[Aighearach]

print $reply_to_user;

die "cannot fork: $!" unless defined ( my $pid = fork() );

if ( $pid ) { #this is the parent.
        exit;
    } else { #this is the child
    open STDOUT, '>/dev/null' or die "Can't write to /dev/null: $!";
        sleep( 10 );
        #do stuff
}

 

update: thanks, Randal. ( btw, you don't have to plug your column each post, you're already famous. ;)

Additional update:Intrepid: I left STDERR alone because it should be connected to the web server error log, which is probably where you want the errors from a CGI.

ncw: Well, I am certainly a lover of doing it the easy way! :) Thanks for that, I've been using a home rolled Daemon module, but I see that I don't need to. But, is this a daemon? Proc::Daemon seems to close STDERR, so then we have to reopen it somehow to get the errors back into the webserver logs where we need them.

Paris Sinclair    |    4a75737420416e6f74686572
[e-mail]    |    205065726c204861636b6572
I wear my Geek Code on my finger.

[merlyn]

You need to have the kid close STDOUT as well. I say this many times in my Web Techniques columns.

-- Randal L. Schwartz, Perl hacker

[ncw]

Or if you are feeling lazy you can do all the above forking, closing, reopening etc with :-

use Proc::Daemon;

#...

Proc::Daemon::Init();

[Anonymous Monk]

Could you provide a sample script? Thanks, David

[Intrepid]

make it more portable this way:

use File::Spec;
 my $devnul = File::Spec->devnull();
print $reply_to_user;
die "cannot fork: $!" unless defined ( my $pid = fork() );
if ( $pid ) { #this is the parent.
        exit;
    } else { #this is the child
open STDOUT, ">$devnul"  or die "Can't write to nowhere: $!";
open STDERR, ">$devnul"  or die "Can't write to nowhere: $!";
        sleep( 10 );
        #do stuff
}

This is a suggestion I have not tried, but BTW on WinNT the string value in $devnul is 'nul'.

Good Meditations,
soren andersen (Intrepid)

Q: What is the sound of several hundred Perler-dogs chasing cool code?
A: YAPC - YAPC - YAPC .. ! :)