G'day LittleJack,

From your post yesterday (Starting out with Dancer and falling at the first hurdle) you're using Dancer2. The link you've provided is for Dancer documentation; the Dancer2 equivalent is https://metacpan.org/dist/Dancer2/view/lib/Dancer2/Manual/Deployment.pod#With-Plack. I had a quick look and can't see any substantial differences; however, it's better to use the right version of the documentation.

"Which perl and which libraries is my Apache (2.4.7) trying to use?"

Either modify your app.psgi, or write a new one, which outputs various version (and perhaps other) information. A very rough, command line example:

$ perl -e '
    use List::Util;
    print "Perl version: $]\n";
    print "List::Util version: $List::Util::VERSION\n";
'
Perl version: 5.034000
List::Util version: 1.56
[download]

Other suggestions:

• Check in your Apache logs for some hints.
• Check which version of mod_perl or mod_perl2 you have installed.
• Do you have any instances of Apache::* that should be Apache2::*.
• Specify a minimum Perl version; e.g. 'use 5.020;'.
  • The first version of perldoc which mentions 'pairmap' and 'pairgrep' is for Perl v5.20: https://perldoc.perl.org/5.20.0/List::Util.
• Specify a minimum List::Util version; e.g. 'use List::Util 1.29 qw{...};'.
  • See https://metacpan.org/dist/Scalar-List-Utils/changes which indicates 'pairmap' and 'pairgrep' were introduced in v1.28 (with a bug) and fixed in v1.29.

Note that I'm attempting to guess what your app.psgi and Apache config look like. Something more concrete from you would be helpful.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.