1Errno(3pm)             Perl Programmers Reference Guide             Errno(3pm)
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NAME

6       Errno - System errno constants
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SYNOPSIS

9           use Errno qw(EINTR EIO :POSIX);
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DESCRIPTION

12       "Errno" defines and conditionally exports all the error constants
13       defined in your system "errno.h" include file. It has a single export
14       tag, ":POSIX", which will export all POSIX defined error numbers.
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16       "Errno" also makes "%!" magic such that each element of "%!" has a non-
17       zero value only if $! is set to that value. For example:
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19           use Errno;
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21           unless (open(FH, "/fangorn/spouse")) {
22               if ($!{ENOENT}) {
23                   warn "Get a wife!\n";
24               } else {
25                   warn "This path is barred: $!";
26               }
27           }
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29       If a specified constant "EFOO" does not exist on the system, $!{EFOO}
30       returns "".  You may use "exists $!{EFOO}" to check whether the
31       constant is available on the system.
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CAVEATS

34       Importing a particular constant may not be very portable, because the
35       import will fail on platforms that do not have that constant.  A more
36       portable way to set $! to a valid value is to use:
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38           if (exists &Errno::EFOO) {
39               $! = &Errno::EFOO;
40           }
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AUTHOR

43       Graham Barr <gbarr@pobox.com>
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46       Copyright (c) 1997-8 Graham Barr. All rights reserved.  This program is
47       free software; you can redistribute it and/or modify it under the same
48       terms as Perl itself.
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52perl v5.16.3                      2019-01-21                        Errno(3pm)
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