Errno(3pm)                                      Perl Programmers Reference Guide                                      Errno(3pm)



NAME
       Errno - System errno constants

SYNOPSIS
           use Errno qw(EINTR EIO :POSIX);

DESCRIPTION
       "Errno" defines and conditionally exports all the error constants defined in your system "errno.h" include file. It has a
       single export tag, ":POSIX", which will export all POSIX defined error numbers.

       "Errno" also makes "%!" magic such that each element of "%!" has a non-zero value only if $! is set to that value. For
       example:

           use Errno;

           unless (open(FH, "/fangorn/spouse")) {
               if ($!{ENOENT}) {
                   warn "Get a wife!\n";
               } else {
                   warn "This path is barred: $!";
               }
           }

       If a specified constant "EFOO" does not exist on the system, $!{EFOO} returns "".  You may use "exists $!{EFOO}" to check
       whether the constant is available on the system.

CAVEATS
       Importing a particular constant may not be very portable, because the import will fail on platforms that do not have that
       constant.  A more portable way to set $! to a valid value is to use:

           if (exists &Errno::EFOO) {
               $! = &Errno::EFOO;
           }

AUTHOR
       Graham Barr <gbarrATpobox.com>

COPYRIGHT
       Copyright (c) 1997-8 Graham Barr. All rights reserved.  This program is free software; you can redistribute it and/or
       modify it under the same terms as Perl itself.



perl v5.12.4                                               2011-11-04                                                 Errno(3pm)