1Task::Weaken(3)       User Contributed Perl Documentation      Task::Weaken(3)
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NAME

6       Task::Weaken - Ensure that a platform has weaken support
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DESCRIPTION

9       One recurring problem in modules that use Scalar::Util's "weaken" func‐
10       tion is that it is not present in the pure-perl variant.
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12       While this isn't necesarily always a problem in a straight CPAN-based
13       Perl environment, some operating system distributions only include the
14       pure-Perl versions, don't include the XS version, and so weaken is then
15       "missing" from the platform, despite passing a dependency on
16       Scalar::Util successfully.
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18       Most notably this is RedHat Linux at time of writing, but other come
19       and go and do the same thing, hence "recurring problem".
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21       The normal solution is to manually write tests in each distribution to
22       ensure that "weaken" is available.
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24       This restores the functionality testing to a dependency you do once in
25       your Makefile.PL, rather than something you have to write extra tests
26       for each time you write a module.
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28       It should also help make the package auto-generators for the various
29       operating systems play more nicely, because it introduces a dependency
30       that they have to have a proper weaken in order to work.
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32       How this Task works
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34       Part of the problem seems to stem from the fact that some distributions
35       continue to include modules even if they fail some of their tests.
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37       To get around that for this module, it will do a few dirty tricks.
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39       If Scalar::Util is not available at all, it will issue a normal depen‐
40       dency on the module. However, if Scalar::Util is relatively new ( it is
41       >= 1.19 ) and the module does not have weaken, the install will bail
42       out altogether with a long error encouraging the user to seek support
43       from their vendor (this problem happens most often in vendor-packaged
44       Perl versions).
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46       This distribution also contains tests to ensure that weaken is avail‐
47       able using more normal methods.
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49       So if your module uses "weaken", you can just add the following to your
50       Module::Install-based Makefile.PL (or equivalent).
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52         requires 'Task::Weaken' => 0;
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AUTHOR

55       Adam Kennedy <adamk@cpan.org>, <http://ali.as/>
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SEE ALSO

58       Task, Scalar::Util, <http://ali.as/>
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61       Copyright 2006 - 2007 Adam Kennedy.
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63       This program is free software; you can redistribute it and/or modify it
64       under the same terms as Perl itself.
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66       The full text of the license can be found in the LICENSE file included
67       with this module.
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71perl v5.8.8                       2007-11-13                   Task::Weaken(3)
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