It's been a while since I wrote any system code, and I was expermenting with nested closures. I came up with this gem, but wondered if you peeps could take a quick look.

I'd be interested in your comments on the safety of the system level calls and the s"appropriate" use of the nested closures. 

#!/usr/bin/perl -w

use strict;
use POSIX ":sys_wait_h";

$SIG{CHLD} = sub {wait};

sub logger {

    my $file = shift;
    my $handle;

    open($handle,">$file") || die "in pain: $file: $!";

    select($handle); $| =1; select(STDOUT);

    return sub {

        my $prefix = shift;

        return sub { print $handle "$prefix ".shift()."\n" };
    };
}

# for demo purposes, just to get some overlap

my $warn = logger("warnings");
my $error = logger("errors");

my @identity = qw(identity1 identity2 identity3 identity4);

foreach my $i (1..4) {

    my $identity = shift(@identity);

    unless (my $pid = fork()) {

        my $wlog = &$warn("$identity: ");
        my $elog = &$error("$identity: ");

        # make things a little more tidy

        sub logwarn { &$wlog(shift); }
        sub logerror { &$elog(shift); }

        foreach my $t (1..3) {

            sleep 2;

            logwarn("random warning $t");
            logerror("random error $t");
        }

        exit(0);
    }

    sleep(2);
}

my $kid;

do {

    $kid = waitpid(-1,&WNOHANG);

} until $kid == -1;

[download]

--
Brother Marvell

¤

In reply to safety in system calls by marvell

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • 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! —
  • 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:
    & &amp;
    < &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.