Errno - System errno constants
use Errno qw(EINTR EIO :POSIX);
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
:POSIX
On Windows, Errno also defines and conditionally exports all the Winsock error constants defined in your system WinError.h include file. These are included in a second export tag, :WINSOCK.
: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.
EFOO
$!{EFOO}
""
exists $!{EFOO}
Perl automatically loads Errno the first time you use %!, so you don't need an explicit use.
use
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; }
Graham Barr <gbarr@pobox.com>
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.
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cpanm
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