---
name: "Errno"
section: "3pm"
platform: "linux"
package: "perl-5.005-doc"
version: "5.005.03-7.1"
release: "Debian 2.2 (Potato)"
platforms: ["linux"]
url: "https://new.carta.tech/Errno/3pm"
---

# Errno(3pm)

System errno constants

## 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, eg

```
    use Errno;

    unless (open(FH, "/fangorn/spouse")) {
        if ($!{ENOENT}) {
            warn "Get a wife!\n";
        } else {
            warn "This path is barred: $!";
        }
    }
```

## 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.