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Inline-FAQ - 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. ( 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.


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 role 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 (unless, you've done something to override this automatic process - such as using the DIRECTORY config option, or using the PERL_INLINE_DIRECTORY environment variable). You can move that to ./.Inline and it will continue to work if you want togive 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 they're needed. :)

What is the best way to package Inline code for CPAN?

This distribution includes Inline::MakeMaker, described below, which takes special steps during the installation of your module to make sure the code gets compiled and installed, rather than compiled by users at runtime. But, users of your module need to install Inline and the language support module like Inline::CPP as prerequisites for your module.

A better way to distribute your module is with Inline::Module, which takes special steps to remove dependencies on Inline::* and convert it to a plain XS module during the construction of your distribution before you upload it to CPAN. It also integrates easily with Dist::Zilla and other modern authoring tools for a more streamlined authoring experience.

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' + Make sure NAME matches your package name ('Foo'), or => begins with 'Foo::'. + If you want to quiet a harmless warning that will => appear when the module is loaded via "require", do "Inline->init();". See => "Writing Modules with Inline" in the Inline pod for details. + Make sure => VERSION matches $Foo::VERSION. This must be a string (not a number) => matching /^\d\.\d\d$/ + 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;
  3. now you have the Perl in one file and the C in the other. The C code must be

in a subdirectory. + 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. + Run 'perl Makefile.PL' + Run 'make test' + Get the MD5 key from blib/arch/auto/Math/Simple/Simple.inl + Edit blib/lib/Math/ Change src/Simple.c to 02c61710cab5b659efc343a9a830aa73 (the MD5 key)

  1. Run 'make ppd'

  2. Edit 'Math-Simple.ppd'. Fill in AUTHOR and ABSTRACT if you wish. Then


      <CODEBASE HREF="" />


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

        tar cvf Math-Simple.tar blib
        gzip --best Math-Simple.tar
  2. Run:

        tar cvf Math-Simple-1.23.tar Math-Simple.ppd Math-Simple.tar.gz
        gzip --best Math-Simple-1.23.tar
  3. Distribute Math-Simple-1.23.tar.gz with the following instructions:

    1. Run:

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

    2. Run 'ppm install Math-Simple.ppd'

    3. Delete Math-Simple.tar and Math-Simple.ppd.

    4. 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

Why does C/t/09parser.t fail on Cygwin ?

It doesn't always fail on Cygwin, but if you find that it produces "unable to remap .... to same address as parent" errors during the build phase, then it's time for you to run rebaseall.

See and, if needed, seek further help from the Cygwin mailing list.