man Errno () - System errno constants

NAME

Errno - System errno constants

SYNOPSIS

    use Errno qw(EINTR EIO :POSIX);

DESCRIPTION

CWErrno defines and conditionally exports all the error constants defined in your system CWerrno.h include file. It has a single export tag, CW:POSIX, which will export all POSIX defined error numbers.

CWErrno also makes CW%! magic such that each element of CW%! has a non-zero value only if CW$! 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 CWEFOO does not exist on the system, CW$!{EFOO} returns CW"". You may use CWexists $!{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 CW$! 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.