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.
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 .
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 .
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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