Inline-FAQ(3) The Inline FAQ


Welcome to the official Inline FAQ. In this case, FAQ means:

    Formerly Answered Questions

This is a collection of old, long-winded emails that myself and others have sent to the Inline mailing list. ([email protected]) They have been reviewed and edited for general Inline edification. Some of them may be related to a specific language. They are presented here in a traditional FAQ layout.

General Inline

Since there is only a handful of content so far, all FAQs are currently under this heading.

How disposable is a .Inline or _Inline directory?

I probably need to be more emphatic about the roll of _Inline/ cache directories. Since they are created automatically, they are completely disposable. I delete them all the time. And it is fine to have a different one for each project. In fact as long as you don't have ~/.Inline/ defined, Inline will create a new ./_Inline directory. You can move that to ./.Inline and it will continue to work if you want to give it more longevity and hide it from view. There is a long complicated list of rules about how [_.]Inline/ directories are used/created. But it was designed to give you the most flexibility/ease-of-use. Never be afraid to nuke 'em. They'll just pop right back next time. :)

Whatever happened to the SITE_INSTALL option?

SITE_INSTALL is gone. I was going to leave it in and change the semantics, but thought it better to remove it, so people wouldn't try to use it the old way. There is now _INSTALL_ (but you're not supposed to know that :). It works magically through the use of Inline::MakeMaker. I explained this earlier but it's worth going through again because it's the biggest change for 0.40. Here's how to 'permanently' install an Inline extension (Inline based module) with 0.40:

    1) Create a module with Inline.
    2) Test it using the normal/local _Inline/ cache.
    3) Create a Makefile.PL (like the one produced by h2xs)
    4) Change 'use ExtUtils::MakeMaker' to 'use Inline::MakeMaker'
    5) In the Makefile.PL's WriteMakefile() insert:
            'Inline::MakeMaker'     => 0.45,
            'ExtUtils::MakeMaker'   => 6.52,
       (See the "Writing Modules with Inline" section of Inline.pod for
        an explanation/elaboration.)
    6) Change your 'use Inline C => DATA' to 'use Inline C => DATA => NAME
       => Foo => VERSION => 1.23'
    7) Make sure NAME matches your package name ('Foo'), or begins with
    8) Make sure VERSION matches $Foo::VERSION. This must be a string (not a
       number) matching /^\d\.\d\d$/
    9) Do the perl/make/test/install dance (thanks binkley :)

With Inline 0.41 (or thereabouts) you can skip steps 3 & 4, and just say 'perl -MInline=INSTALL ./'. This will work for non-Inline modules too. It will become the defacto standard (since there is no easy standard) way of installing a Perl module. It will allow Makefile.PL parameters 'perl -MInline=INSTALL ./ - PREFIX=/home/ingy/perl' and things like that. It will also make use of a MANIFEST if you provide one.

How do I create a binary distribution using Inline?

I've figured out how to create and install a PPM binary distribution; with or without distributing the C code! And I've decided to share it with all of you :)

NOTE: Future versions of Inline will make this process a one line command. But for now just use this simple recipe.


The Inline 0.40 distribution comes with a sample extension module called Math::Simple. Theoretically you could distribute this module on CPAN. It has all the necessary support for installation. You can find it in Inline-0.40/modules/Math/Simple/. Here are the steps for converting this into a binary distribution *without* C source code.

NOTE: The recipient of this binary distribution will need to have the module installed. This module requires a lot of other CPAN modules. ActivePerl (available for Win32, Linux, and Solaris) has all of these bundled. While ActivePerl isn't required, it makes things (a lot) easier.

1) cd Inline-0.40/Math/Simple/

2) Divide into two files:

    ---8<--- (
    package Math::Simple;
    use strict;
    require Exporter;
    @Math::Simple::ISA = qw(Exporter);
    @Math::Simple::EXPORT = qw(add subtract);
    $Math::Simple::VERSION = '1.23';
    use Inline (C => 'src/Simple.c' =>
                NAME => 'Math::Simple',
                VERSION => '1.23',
    ---8<--- (src/Simple.c)
    int add (int x, int y) {
        return x + y;
    int subtract (int x, int y) {
        return x - y;

So now you have the Perl in one file and the C in the other. The C code must be in a subdirectory.

3) Note that I also changed the term 'DATA' to the name of the C file. This will work just as if the C were still inline.

4) Run 'perl Makefile.PL'

5) Run 'make test'

6) Get the MD5 key from 'blib/arch/auto/Math/Simple/Simple.inl'

7) Edit 'blib/lib/Math/'. Change 'src/Simple.c' to '02c61710cab5b659efc343a9a830aa73' (the MD5 key)

8) Run 'make ppd'

9) Edit 'Math-Simple.ppd'. Fill in AUTHOR and ABSTRACT if you wish. Then change:

    <CODEBASE HREF="" />


    <CODEBASE HREF="Math-Simple.tar.gz" />

10) Run:

    tar cvf Math-Simple.tar blib
    gzip --best Math-Simple.tar

11) Run:

    tar cvf Math-Simple-1.23.tar Math-Simple.ppd Math-Simple.tar.gz
    gzip --best Math-Simple-1.23.tar

12) Distribute Math-Simple-1.23.tar.gz with the following instructions:

A) Run:

    gzip -d Math-Simple-1.23.tar.gz
    tar xvzf Math-Simple-1.23.tar

B) Run 'ppm install Math-Simple.ppd'

C) Delete Math-Simple.tar and Math-Simple.ppd.

D) Test with:

    perl -MMath::Simple -le 'print add(37, 42)'


That's it. The process should also work with zip instead of tar, but I haven't tried it.

The recipient of the binary must have Perl built with a matching architecture. Luckily, ppm will catch this.

For a binary dist *with* C source code, simply omit steps 2, 3, 6, and 7.

If this seems too hard, then in a future version you should be able to just type:

    make ppm