NAME

Perl::Critic::Policy::InputOutput::ProhibitTwoArgOpen - Write open $fh, q{<}, $filename; instead of open $fh, "<$filename";.

AFFILIATION

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

DESCRIPTION

The three-argument form of open (introduced in Perl 5.6) prevents subtle bugs that occur when the filename starts with funny characters like '>' or '<'. The IO::File module provides a nice object-oriented interface to filehandles, which I think is more elegant anyway.

open( $fh, '>output.txt' );          # not ok
open( $fh, q{>}, 'output.txt' );     # ok

use IO::File;
my $fh = IO::File->new( 'output.txt', q{>} ); # even better!

It's also more explicitly clear to define the input mode of the file, as in the difference between these two:

open( $fh, 'foo.txt' );       # BAD: Reader must think what default mode is
open( $fh, '<', 'foo.txt' );  # GOOD: Reader can see open mode

CONFIGURATION

This Policy is not configurable except for the standard options.

NOTES

The only time you should use the two-argument form is when you re-open STDIN, STDOUT, or STDERR. But for now, this Policy doesn't provide that loophole.

SEE ALSO

IO::Handle

IO::File

AUTHOR

Jeffrey Ryan Thalhammer <thaljef@cpan.org>

COPYRIGHT

Copyright (C) 2005-2007 Jeffrey Ryan Thalhammer. All rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.