Florian Ragwitz > perl-5.17.4 > Errno

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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.

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