Errno(3p) Perl Programmers Reference Guide Errno(3p) #

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

NNAAMMEE #

 Errno - System errno constants

SSYYNNOOPPSSIISS #

     use Errno qw(EINTR EIO :POSIX);

DDEESSCCRRIIPPTTIIOONN #

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

 On Windows, "Errno" also defines and conditionally exports all the
 Winsock error constants defined in your system _W_i_n_E_r_r_o_r_._h include file.
 These are included in a second export tag, ":WINSOCK".

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

     my $fh;
     unless (open($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.

 Perl automatically loads "Errno" the first time you use "%!", so you
 don't need an explicit "use".

CCAAVVEEAATTSS #

 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;
     }

AAUUTTHHOORR #

 Graham Barr <gbarr@pobox.com>

CCOOPPYYRRIIGGHHTT #

 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 v5.36.3 2024-03-20 Errno(3p)