1Perl::Critic::Policy::IUPnseperurlt:OC:uoCtnrptiurttii:bc:u:Pt:rePodohliPibecirytl:T:wDIoonAcpruugmtOeOpnuettnap(tu3it)o:n:ProhibitTwoArgOpen(3)
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NAME

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

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

13       The three-argument form of "open" (introduced in Perl 5.6) prevents
14       subtle bugs that occur when the filename starts with funny characters
15       like '>' or '<'.  The IO::File module provides a nice object-oriented
16       interface to filehandles, which I think is more elegant anyway.
17
18         open( $fh, '>output.txt' );          # not ok
19         open( $fh, q{>}, 'output.txt' );     # ok
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21         use IO::File;
22         my $fh = IO::File->new( 'output.txt', q{>} ); # even better!
23
24       It's also more explicitly clear to define the input mode of the file,
25       as in the difference between these two:
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27         open( $fh, 'foo.txt' );       # BAD: Reader must think what default mode is
28         open( $fh, '<', 'foo.txt' );  # GOOD: Reader can see open mode
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30       This policy will not complain if the file explicitly states that it is
31       compatible with a version of perl prior to 5.6 via an include
32       statement, e.g. by having "require 5.005" in it.
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CONFIGURATION

35       This Policy is not configurable except for the standard options.
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NOTES

38       There are two cases in which you are forced to use the two-argument
39       form of open. When re-opening STDIN, STDOUT, or STDERR, and when doing
40       a safe pipe open, as described in perlipc.
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SEE ALSO

43       IO::Handle
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45       IO::File
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AUTHOR

48       Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>
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51       Copyright (c) 2005-2011 Imaginative Software Systems.  All rights
52       reserved.
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54       This program is free software; you can redistribute it and/or modify it
55       under the same terms as Perl itself.
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59perl v5.28.1          Perl::Critic2:0:1P9o-l0i2c-y0:2:InputOutput::ProhibitTwoArgOpen(3)
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