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

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
I was confused by this as well. My cause to delve into IO::Socket was a breakdown of my LWP modules.

Go to your Perl source can check out:

the directory ext/Errno

This is where these strings are actually obtained and made into the Errno.pm module which in turn gives rise to %!.

What is going on here is that at make time Errno_pm.PL actually checks the cpp output to get a list of headers to scan. This output comes from something along the lines of "cpp your cpp flags errno.c". "errno.c" has a single line "#include <errno.h> Then it will scan all of these header files for #defines. (check out /usr/lib/errno.h or /usr/lib/asm/errno.h if you have it). Taking these defines, it will write the code for "Errno.pm" which ultimately lives in "lib/perl5/5.6.0/<arch>/Errno.pm.

The values for %! are supplied via a tied hash from Errno.pm.

Why do I know this? Well because shipped with RedHat did not correctly report all of the headers to scan. When the IO::Socket went to test against $!{EINPROGRESS} it did not match. It was always giving me "Timeout" messages. :( After tracing this through I found the defective output from cpp and the rest is history.

You need the updated cpp that RedHat supplies. This version (dated Dec 18, 2000) works correctly.

J


In reply to Re: $! or &Errno or $!{} by jlawrenc
in thread $! or &Errno or $!{} by tadman

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!
  • 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?
    Username:
    Password:

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

    How do I use this? | Other CB clients
    Other Users?
    Others meditating upon the Monastery: (11)
    As of 2015-07-07 14:26 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (89 votes), past polls