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Errno.3perl

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 <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.