Beefy Boxes and Bandwidth Generously Provided by pair Networks
No such thing as a small change

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

Proc::Daemon is a particularly useful module for anyone writing unix daemon's (a program which runs in the background with no user input). It detaches your program from the its parent, allowing it to run undisturbed by the parent, you logging out, or the parent waiting for it to die.

This is a simple module and most of the code in it is contained in The Perl Cookbook, however this module brings it together in a neatly wrapped package so you don't have to remember any of those horrid details (like the double fork, setsid, chdir, reopen STDOUT etc)!

Use it like this

use Proc::Daemon; Proc::Daemon::Init();
That is it!

You'd quite likely like to re-open STDOUT & STDERR to a log file though, like this :-

open(STDOUT, ">>$LOG") or die "Failed to re-open STDOUT to $LOG"; open(STDERR, ">&STDOUT") or die "Failed to re-open STDERR to STDOUT";
I've used it quite a few times now, for writing real daemons, sendmail filters which need to run for a long time (eg email to SMS), for detaching processes from crontab, and for long running CGI programs (which don't need to return a response to the user).

Warning: This module is unlikely to work under Windows, though it probably could be made to.

Verdict: Small but perfectly formed!

In reply to Proc::Daemon by ncw

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, 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, 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.
  • Log In?

    What's my password?
    Create A New User
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others exploiting the Monastery: (4)
    As of 2021-04-17 21:15 GMT
    Find Nodes?
      Voting Booth?

      No recent polls found