Chapter 4

Listing 4 10. Nonportable count_args.pl

#!/usr/bin/perl  w

use Data::Counter qw(count);

print count(@ARGV), "\n";

The solution to this problem is shown in Listing 4 11. ExtUtils::MakeMaker 

will execute any script ending in .PL at build time and use the output as the source 

for the script to install. The name of the file to be generated must be the name of 

the script preceding the .PL. This follows the pattern set by Makefile.PL generating 

Makefile. In the example shown, to generate count_args.pl, I created a file named 

count_args.pl.PL. This script uses the Config module to generate the correct perl

execution line for the start of the script file.

Listing 4 11. Portable count_args.pl.PL

use Config; # used to get at startperl

# open output script and make it executable

open OUT,">count_args.pl" or die "Can t create count_args.pl: $!";

chmod(0755, "count_args.pl");

# output perl startup line

print OUT $Config{startperl}, "  w \n";

# output the rest of the script

print OUT q{

  use Data::Counter;

  print Data::Counter::count(@ARGV), "\n";

};

This mechanism can be used to do more than just extract platform information 

from the Config module. Some overly clever module authors use .PL scripts in zany 

code generation schemes to gain flexibility and performance. I'll admit to being 

guilty of this charge, but I hesitate to suggest the practice to the sane!

Building the Distribution Archive

Building the distribution archive with ExtUtils::MakeMaker is as simple as running 

make dist (after running perl Makefile.PL, of course). This is the command that 

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