errno(3)
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!0;} else {warn "This path is barred: $!";}
- }
- If a specified constant "EFOO" does not exist on the sys
tem, $!{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.