Beefy Boxes and Bandwidth Generously Provided by pair Networks
XP is just a number

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
kill(0, $pid) will return true even if the $pid process is a zombie. By setting $SIG{CHLD}='IGNORE'; before forking, you're having the parent process reap the zombie child upon receiving SIGCHLD, causing your call to kill(0, ...) to then work as expected.

I believe (someone correct me please) that the default perl handler for SIGCHLD is to do nothing. It is left up to the programmer to reap the child processes manually (via waitpid, or setting 'IGNORE').

    In a loop, testing the aforementioned condition, and killing the childs if the condition is met

Even after killing the children (e.g. kill(9, $pid), though I hope you're nicer with kill(15, $pid)), you still need to reap them. You're doing fine since you set 'IGNORE'.

In reply to Re: Monitoring child processes by repellent
in thread Monitoring child processes by rovf

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: (10)
    As of 2020-11-30 14:52 GMT
    Find Nodes?
      Voting Booth?

      No recent polls found