Perl::Critic::Policy::InputOutput::RequireCheckedSyscalls - Return value of flagged function ignored.


This Policy is part of the core Perl::Critic distribution.


This performs identically to InputOutput::RequireCheckedOpen/Close except that this is configurable to apply to any function, whether core or user-defined.

If your module uses Fatal, Fatal::Exception, or autodie then any functions wrapped by those modules will not trigger this policy. For example:

    use Fatal qw(open);
    open my $fh, $filename;  # no violation
    close $fh;               # yes violation

    use autodie;
    open $filehandle, $mode, $filename;   # no violation

Currently, autodie is not properly treated as a pragma; its lexical effects aren't taken into account.


This policy watches for a configurable list of function names. By default, it applies to open, print, say and close. You can override this to set it to a different list of functions with the functions and exclude_functions settings. To do this, put entries in a .perlcriticrc file like this:

    functions = open opendir read readline readdir close closedir

We have defined a few shortcuts for creating this list

    functions = :defaults opendir readdir closedir

    functions = :builtins

    functions = :all

The :builtins shortcut above represents all of the builtin functions that have error conditions (about 65 of them, many of them rather obscure).

You can require checking all builtins except print by combining the functions and exclude_functions:

    functions = :builtins
    exclude_functions = print

This is a lot easier to read than the alternative.

The :all is the insane case: you must check the return value of EVERY function call, even return and exit. Yes, this "feature" is overkill and is wasting CPU cycles on your computer by just existing. Nyah nyah. I shouldn't code after midnight.

If you create a module that exports autodie you can tell this policy about it with the autodie_modules setting:

    autodie_modules = My::Thing


Initial development of this policy was supported by a grant from the Perl Foundation.

This policy module is based heavily on policies written by Andrew Moore <>.


Chris Dolan <>


Copyright (c) 2007-2011 Chris Dolan. Many rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license can be found in the LICENSE file included with this module.