GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  PERL::CRITIC::POLICY::INPUTOUTPUT::PROHIBITEXPLICITSTDIN (3)

.ds Aq ’

NAME

Perl::Critic::Policy::InputOutput::ProhibitExplicitStdin - Use "<>" or "<ARGV>" or a prompting module instead of "<STDIN>".

CONTENTS

AFFILIATION

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

DESCRIPTION

Perl has a useful magic filehandle called *ARGV that checks the command line and if there are any arguments, opens and reads those as files. If there are no arguments, *ARGV behaves like *STDIN instead. This behavior is almost always what you want if you want to create a program that reads from STDIN. This is often written in one of the following two equivalent forms:



  while (<ARGV>) {
    # ... do something with each input line ...
  }
  # or, equivalently:
  while (<>) {
    # ... do something with each input line ...
  }



If you want to prompt for user input, try special purpose modules like IO::Prompt.

CONFIGURATION

This Policy is not configurable except for the standard options.

CAVEATS

Due to a bug in the current version of PPI (v1.119_03) and earlier, the readline operator is often misinterpreted as less-than and greater-than operators after a comma. Therefore, this policy misses important cases like



  my $content = join , <STDIN>;



because it interprets that line as the nonsensical statement:



  my $content = join , < STDIN >;



When that PPI bug is fixed, this policy should start catching those violations automatically.

CREDITS

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

AUTHOR

Chris Dolan <cdolan@cpan.org>

COPYRIGHT

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

Search for    or go to Top of page |  Section 3 |  Main Index


perl v5.20.3 PERL::CRITIC::POLICY::INPUTOUTPUT::PROHIBITEXPLICITSTDIN (3) 2016-04-03

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.