


ext::Errno::ErrnoPerl3Programmers Referenext::Errno::Errno_pm(3p)


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 sys-
       tem, "$!{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 <gbarr@pobox.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.







2001-05-24                 perl v5.6.1                          1


