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Mark Dominus
Perl Paraphernalia

There are a good few conventions for making modules and, perlmod is a bit too condensed to learn it IMHO, although an excellent reference.

Sadly most of the knowledge I've gleemed on this subject is in the pages of Debugging Perl, The Perl Cookbook and Object Oriented Perl, so I can't readily submit URL's for the salient points, all these books give a well rounded look at modules and their creation and use, from different angles, with little overlap. If I had to point to one book to use, for this and other reasons it'd be the Cook Book. HTH.

Your code might benefit from indentation and you don't need the brackets around the variables being declared.

You might lessen your future efforts further by making the functions more generic, maintainable and robust:

• Passing the list of recipients as a array reference. Try a closure so you can set up the recipients once. If it is static.
• Consider whether prototypes are useful, in some cases you can use them to enforce correct use of your functions.
• Add validation as far as possible. Unless this is purely for your own benefit, it is polite to inform users of why things have failed. So to that end consider returning the results from the system call.
• Add Pod to the functions or perhaps good commenting, examples of usage, and such.

You were asking for Module specific stuff, and I fear I may be repeating things, you already know. A more precise set of goals to enable you to get `moduled' are:

1. Learn how to set the module in a remote and common directory. @INC, use lib or -i
2. Decide which functions are private or public. use Exporter and @Exporter
3. Ensure your code is legible and well commented. Here is a good place to begin.
4. Look to CPAN to see if what you're doing has already been done.

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The first thing you must do is read through the perlmod documentation so you understand exactly what it is modules do and how they interact with the calling program. I would also recommend strongly that you read the entry on the @INC variable in perlvar. Understanding this is also important.

After that, determine the directory structure and name for your module, like Mymods/Thismod.pm, create the file and place your subs within the skeleton below:

package Mymods::Thismod;

### YOUR CODE GOES HERE ###

1;
[download]

If you have read the documentation recommended then this will all come clear to you.

Update Make sure you read through frankus' post above too, all the comments he makes about your code are well worth following.

$japh->{'Caillte'} = $me;

BEGIN {
  require "/var/www/cgi-bin/snmplib.pl"; 
}
[download]

If you do this you will quickly encounter the following problems:
1. Tracking down where a routine comes from will become difficult.
2. Scripts will reuse variables and subroutine names unbeknownst to you, and they will collide.
3. Because of hardcoded paths it will be very hard for you to test any changes without modifying production.
4. Without a clear division between executable and non-executable code, people are likely to put actions into scripts where they do not belong.
In addition the speed difference between doing the above and doing it right with modules is insignificant if you have ever learned to write modules.

So here is a template for stealing routines from existing code and putting them into a procedural module.

1. Decide what module the routine belongs in. If the answer is none that you have, start a new module.
2. To start a new module create a file Foo.pm, and in it type the following template:

   package Foo;
   use Exporter;
   @ISA = 'Exporter';
   @EXPORT_OK = qw();
   use strict;
   
   # Your subs will go here.
   1;
   [download]

   The word "Foo" must match the module name (with the usual conversion between the package separator :: and the path /).
3. Copy the subroutine into the module.
4. Put the name of the subroutine in the @EXPORT_OK list.
5. Comment out the original subroutine.
6. Put use Foo qw(sub_name); back in the original script.
7. Test. (Often the subroutine will have dependencies that also need to go into the module.)
8. Roll out.
As for the location of modules, that is what lib is for. I personally have a custom configuration loader that will (among other things) transparently do the right lib invocations for me. In development pick up my copy of stuff in CVS. In production pick up the production copy of the same. The exact layout and development of that kind of functionality is a site decision. (Having this available has made testing and development much easier...)

Happy Perling.
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Zigster