NAME
    Inline - Write Perl Subroutines in Other Programming Languages

SYNOPSIS
        use Inline C;

        print "9 + 16 = ", add(9, 16), "\n";
        print "9 - 16 = ", subtract(9, 16), "\n";

        __END__
        __C__
        int add(int x, int y) {
          return x + y;
        }

        int subtract(int x, int y) {
          return x - y;
        }

DESCRIPTION
    The Inline module allows you to put source code from other programming
    languages directly "inline" in a Perl script or module. The code is
    automatically compiled as needed, and then loaded for immediate access
    from Perl.

    Inline saves you from the hassle of having to write and compile your own
    glue code using facilities like XS or SWIG. Simply type the code where
    you want it and run your Perl as normal. All the hairy details are
    handled for you. The compilation and installation of your code chunks
    all happen transparently; all you will notice is the delay of
    compilation on the first run.

    The Inline code only gets compiled the first time you run it (or
    whenever it is modified) so you only take the performance hit once. Code
    that is Inlined into distributed modules (like on the CPAN) will get
    compiled when the module is installed, so the end user will never notice
    the compilation time.

    Best of all, it works the same on both Unix and Microsoft Windows. See
    Inline- Support for support information.

  Why Inline?
    Do you want to know "Why would I use other languages in Perl?" or "Why
    should I use Inline to do it?"? I'll try to answer both.

    Why would I use other languages in Perl?
        The most obvious reason is performance. For an interpreted language,
        Perl is very fast. Many people will say "Anything Perl can do, C can
        do faster". (They never mention the development time :-) Anyway, you
        may be able to remove a bottleneck in your Perl code by using
        another language, without having to write the entire program in that
        language. This keeps your overall development time down, because
        you're using Perl for all of the non-critical code.

        Another reason is to access functionality from existing API-s that
        use the language. Some of this code may only be available in binary
        form. But by creating small subroutines in the native language, you
        can "glue" existing libraries to your Perl. As a user of the CPAN,
        you know that code reuse is a good thing. So why throw away those
        Fortran libraries just yet?

        If you are using Inline with the C language, then you can access the
        full internals of Perl itself. This opens up the floodgates to both
        extreme power and peril.

        Maybe the best reason is "Because you want to!". Diversity keeps the
        world interesting. TMTOWTDI!

    Why should I use Inline to do it?
        There are already two major facilities for extending Perl with C.
        They are XS and SWIG. Both are similar in their capabilities, at
        least as far as Perl is concerned. And both of them are quite
        difficult to learn compared to Inline.

        There is a big fat learning curve involved with setting up and using
        the XS environment. You need to get quite intimate with the
        following docs:

        *   perlxs

        *   perlxstut

        *   perlapi

        *   perlguts

        *   perlmod

        *   h2xs

        *   xsubpp

        *   ExtUtils::MakeMaker

        With Inline you can be up and running in minutes. There is a C
        Cookbook with lots of short but complete programs that you can
        extend to your real-life problems. No need to learn about the
        complicated build process going on in the background. You don't even
        need to compile the code yourself. Inline takes care of every last
        detail except writing the C code.

        Perl programmers cannot be bothered with silly things like
        compiling. "Tweak, Run, Tweak, Run" is our way of life. Inline does
        all the dirty work for you.

        Another advantage of Inline is that you can use it directly in a
        script. You can even use it in a Perl one-liner. With XS and SWIG,
        you always set up an entirely separate module. Even if you only have
        one or two functions. Inline makes easy things easy, and hard things
        possible. Just like Perl.

        Finally, Inline supports several programming languages (not just C
        and C++). As of this writing, Inline has support for C, C++, Java,
        Python, Ruby, Tcl, Assembler, Basic, Guile, Befunge, Octave, Awk,
        BC, TT (Template Toolkit), WebChat and even PERL. New Inline
        Language Support Modules (ILSMs) are regularly being added. See
        Inline-API for details on how to create your own ILSM.

USING THE INLINE.PM MODULE
    Inline is a little bit different than most of the Perl modules that you
    are used to. It doesn't import any functions into your namespace and it
    doesn't have any object oriented methods. Its entire interface (with two
    minor exceptions) is specified through the 'use Inline ...' command.

    This section will explain all of the different ways to "use Inline". If
    you want to begin using C with Inline immediately, see
    Inline::C-Cookbook.

  The Basics
    The most basic form for using Inline is:

        use Inline X => "X source code";

    where 'X' is one of the supported Inline programming languages. The
    second parameter identifies the source code that you want to bind to
    Perl. The source code can be specified using any of the following
    syntaxes:

    The DATA Keyword.
            use Inline Java => 'DATA';

            # Perl code goes here ...

            __DATA__
            __Java__
            /* Java code goes here ... */

        The easiest and most visually clean way to specify your source code
        in an Inline Perl program is to use the special "DATA" keyword. This
        tells Inline to look for a special marker in your "DATA"
        filehandle's input stream. In this example the special marker is
        "__Java__", which is the programming language surrounded by double
        underscores.

        In case you've forgotten, the "DATA" pseudo file is comprised of all
        the text after the "__END__" or "__DATA__" section of your program.
        If you're working outside the "main" package, you'd best use the
        "__DATA__" marker or else Inline will not find your code.

        Using this scheme keeps your Perl code at the top, and all the ugly
        Java stuff down below where it belongs. This is visually clean and
        makes for more maintainable code. An excellent side benefit is that
        you don't have to escape any characters like you might in a Perl
        string. The source code is verbatim. For these reasons, I prefer
        this method the most.

        The only problem with this style is that since Perl can't read the
        "DATA" filehandle until runtime, it obviously can't bind your
        functions until runtime. The net effect of this is that you can't
        use your Inline functions as barewords (without predeclaring them)
        because Perl has no idea they exist during compile time.

    The FILE and BELOW keywords.
            use Inline::Files;
            use Inline Java => 'FILE';

            # Perl code goes here ...

            __JAVA__
            /* Java code goes here ... */

        This is the newest method of specifying your source code. It makes
        use of the Perl module "Inline::Files" written by Damian Conway. The
        basic style and meaning are the same as for the "DATA" keyword, but
        there are a few syntactic and semantic twists.

        First, you must say 'use Inline::Files' before you 'use Inline' code
        that needs those files. The special '"DATA"' keyword is replaced by
        either '"FILE"' or '"BELOW"'. This allows for the bad pun idiom of:

            use Inline C => 'BELOW';

        You can omit the "__DATA__" tag now. Inline::Files is a source
        filter that will remove these sections from your program before Perl
        compiles it. They are then available for Inline to make use of. And
        since this can all be done at compile time, you don't have to worry
        about the caveats of the 'DATA' keyword.

        This module has a couple small gotchas. Since Inline::Files only
        recognizes file markers with capital letters, you must specify the
        capital form of your language name. Also, there is a startup time
        penalty for using a source code filter.

        At this point Inline::Files is alpha software and use of it is
        experimental. Inline's integration of this module is also fledgling
        at the time being. One of things I plan to do with Inline::Files is
        to get line number info so when an extension doesn't compile, the
        error messages will point to the correct source file and line
        number.

        My best advice is to use Inline::Files for testing (especially as
        support for it improves), but use DATA for production and
        distributed/CPAN code.

    Strings
            use Inline Java => <<'END';

            /* Java code goes here ... */
            END

            # Perl code goes here ...

        You also just specify the source code as a single string. A handy
        way to write the string is to use Perl's "here document" style of
        quoting. This is ok for small functions but can get unwieldy in the
        large. On the other hand, the string variant probably has the least
        startup penalty and all functions are bound at compile time.

        If you wish to put the string into a scalar variable, please be
        aware that the "use" statement is a compile time directive. As such,
        all the variables it uses must also be set at compile time, "before"
        the 'use Inline' statement. Here is one way to do it:

            my $code;
            BEGIN {
                $code = <<END;

            /* Java code goes here ... */
            END
            }
            use Inline Java => $code;

            # Perl code goes here ...

    The bind() Function
        An alternative to using the BEGIN block method is to specify the
        source code at run time using the 'Inline->bind()' method. (This is
        one of the interface exceptions mentioned above) The "bind()" method
        takes the same arguments as 'use Inline ...'.

            my $code = <<END;

            /* Java code goes here ... */
            END

            Inline->bind(Java => $code);

        You can think of "bind()" as a way to "eval()" code in other
        programming languages.

        Although bind() is a powerful feature, it is not recommended for use
        in Inline based modules. In fact, it won't work at all for
        installable modules. See instructions below for creating modules
        with Inline.

    Other Methods
        The source code for Inline can also be specified as an external
        filename, a reference to a subroutine that returns source code, or a
        reference to an array that contains lines of source code. (Note that
        if the external source file is in the current directory it must be
        specified with a leading '.*' - ie '.*file.ext' instead of simply
        'file.ext'.) These methods are less frequently used but may be
        useful in some situations.

    Shorthand
        If you are using the 'DATA' or 'FILE' methods described above and
        there are no extra parameters, you can omit the keyword altogether.
        For example:

            use Inline 'Java';

            # Perl code goes here ...

            __DATA__
            __Java__
            /* Java code goes here ... */

        or

            use Inline::Files;
            use Inline 'Java';

            # Perl code goes here ...

            __JAVA__
            /* Java code goes here ... */

  More about the DATA Section
    If you are writing a module, you can also use the DATA section for POD
    and AutoLoader subroutines. Just be sure to put them before the first
    Inline marker. If you install the helper module "Inline::Filters", you
    can even use POD inside your Inline code. You just have to specify a
    filter to strip it out.

    You can also specify multiple Inline sections, possibly in different
    programming languages. Here is another example:

        # The module Foo.pm
        package Foo;
        use AutoLoader;

        use Inline C;
        use Inline C => DATA => FILTERS => 'Strip_POD';
        use Inline Python;

        1;

        __DATA__

        sub marine {
            # This is an autoloaded subroutine
        }

        =head1 External subroutines

        =cut

        __C__
        /* First C section */

        __C__
        /* Second C section */
        =head1 My C Function

        Some POD doc.

        =cut

        __Python__
        """A Python Section"""

    An important thing to remember is that you need to have one "use Inline
    Foo => 'DATA'" for each "__Foo__" marker, and they must be in the same
    order. This allows you to apply different configuration options to each
    section.

  Configuration Options
    Inline tries to do the right thing as often as possible. But sometimes
    you may need to override the default actions. This is easy to do. Simply
    list the Inline configuration options after the regular Inline
    parameters. All configuration options are specified as (key, value)
    pairs.

        use Inline (C => 'DATA',
                    DIRECTORY => './inline_dir',
                    LIBS => '-lfoo',
                    INC => '-I/foo/include',
                    PREFIX => 'XXX_',
                    WARNINGS => 0,
                   );

    You can also specify the configuration options on a separate Inline call
    like this:

        use Inline (C => Config =>
                    DIRECTORY => './inline_dir',
                    LIBS => '-lfoo',
                    INC => '-I/foo/include',
                    PREFIX => 'XXX_',
                    WARNINGS => 0,
                   );
        use Inline C => <<'END_OF_C_CODE';

    The special keyword 'Config' tells Inline that this is a
    configuration-only call. No source code will be compiled or bound to
    Perl.

    If you want to specify global configuration options that don't apply to
    a particular language, just leave the language out of the call. Like
    this:

        use Inline Config => WARNINGS => 0;

    The Config options are inherited and additive. You can use as many
    Config calls as you want. And you can apply different options to
    different code sections. When a source code section is passed in, Inline
    will apply whichever options have been specified up to that point. Here
    is a complex configuration example:

        use Inline (Config =>
                    DIRECTORY => './inline_dir',
                   );
        use Inline (C => Config =>
                    LIBS => '-lglobal',
                   );
        use Inline (C => 'DATA',         # First C Section
                    LIBS => ['-llocal1', '-llocal2'],
                   );
        use Inline (Config =>
                    WARNINGS => 0,
                   );
        use Inline (Python => 'DATA',    # First Python Section
                    LIBS => '-lmypython1',
                   );
        use Inline (C => 'DATA',         # Second C Section
                    LIBS => [undef, '-llocal3'],
                   );

    The first "Config" applies to all subsequent calls. The second "Config"
    applies to all subsequent "C" sections (but not "Python" sections). In
    the first "C" section, the external libraries "global", "local1" and
    "local2" are used. (Most options allow either string or array ref forms,
    and do the right thing.) The "Python" section does not use the "global"
    library, but does use the same "DIRECTORY", and has warnings turned off.
    The second "C" section only uses the "local3" library. That's because a
    value of "undef" resets the additive behavior.

    The "DIRECTORY" and "WARNINGS" options are generic Inline options. All
    other options are language specific. To find out what the "C" options
    do, see "Inline::C".

  On and Off
    If a particular config option has value options of 1 and 0, you can use
    the ENABLE and DISABLE modifiers. In other words, this:

        use Inline Config =>
                   FORCE_BUILD => 1,
                   CLEAN_AFTER_BUILD => 0;

    could be reworded as:

        use Inline Config =>
                   ENABLE => FORCE_BUILD,
                   DISABLE => CLEAN_AFTER_BUILD;

  Playing 'with' Others
    Inline has a special configuration syntax that tells it to get more
    configuration options from other Perl modules. Here is an example:

        use Inline with => 'Event';

    This tells Inline to load the module "Event.pm" and ask it for
    configuration information. Since "Event" has a C API of its own, it can
    pass Inline all of the information it needs to be able to use "Event" C
    callbacks seamlessly.

    That means that you don't need to specify the typemaps, shared
    libraries, include files and other information required to get this to
    work.

    You can specify a single module or a list of them. Like:

        use Inline with => qw(Event Foo Bar);

    Currently, "Event" is the only module that works *with* Inline.

    In order to make your module work *with* Inline in this way, your module
    needs to provide a class method called "Inline" that takes an Inline
    language as a parameter (e.g. "C"), and returns a reference to a hash
    with configuration information that is acceptable to the relevant ILSM.
    For C, see C Configuration Options. E.g.:

        my $confighashref = Event->Inline('C'); # only supports C in 1.21
        # hashref contains keys INC, TYPEMAPS, MYEXTLIB, AUTO_INCLUDE, BOOT

    If your module supports ExtUtils::Depends, your function might be as
    simple as this:

        package Module;
        sub Inline {
            my ($class, $lang) = @_;
            return unless $lang eq 'C'; # Inline's error message is good
            require Module::Install::Files;
            +{
                map { (uc($_) =>  ${$Module::Install::Files::{$_}}) } qw(inc libs),
                TYPEMAPS => \@Module::Install::Files::typemaps,
            };
        }

  Inline Shortcuts
    Inline lets you set many configuration options from the command line.
    These options are called 'shortcuts'. They can be very handy, especially
    when you only want to set the options temporarily, for say, debugging.

    For instance, to get some general information about your Inline code in
    the script "Foo.pl", use the command:

        perl -MInline=INFO Foo.pl

    If you want to force your code to compile, even if its already done,
    use:

        perl -MInline=FORCE Foo.pl

    If you want to do both, use:

        perl -MInline=INFO -MInline=FORCE Foo.pl

    or better yet:

        perl -MInline=INFO,FORCE Foo.pl

  The Inline DIRECTORY
    Inline needs a place to build your code and to install the results of
    the build. It uses a single directory named '.Inline/' under normal
    circumstances. If you create this directory in your home directory, the
    current directory or in the directory where your program resides, Inline
    will find and use it. You can also specify it in the environment
    variable "PERL_INLINE_DIRECTORY" or directly in your program, by using
    the "DIRECTORY" keyword option. If Inline cannot find the directory in
    any of these places it will create a '_Inline/' directory in either your
    current directory or the directory where your script resides.

    One of the key factors to using Inline successfully, is understanding
    this directory. When developing code it is usually best to create this
    directory (or let Inline do it) in your current directory. Remember that
    there is nothing sacred about this directory except that it holds your
    compiled code. Feel free to delete it at any time. Inline will simply
    start from scratch and recompile your code on the next run. If you have
    several programs that you want to force to recompile, just delete your
    '.Inline/' directory.

    It is probably best to have a separate '.Inline/' directory for each
    project that you are working on. You may want to keep stable code in the
    <.Inline/> in your home directory. On multi-user systems, each user
    should have their own '.Inline/' directories. It could be a security
    risk to put the directory in a shared place like "/tmp/".

  Debugging Inline Errors
    All programmers make mistakes. When you make a mistake with Inline, like
    writing bad C code, you'll get a big error report on your screen. This
    report tells you where to look to do the debugging. Some languages may
    also dump out the error messages generated from the build.

    When Inline needs to build something it creates a subdirectory under
    your "DIRECTORY/build/" directory. This is where it writes all the
    components it needs to build your extension. Things like XS files,
    Makefiles and output log files.

    If everything goes OK, Inline will delete this subdirectory. If there is
    an error, Inline will leave the directory intact and print its location.
    The idea is that you are supposed to go into that directory and figure
    out what happened.

    Read the doc for your particular Inline Language Support Module for more
    information.

  The 'config' Registry File
    Inline keeps a cached file of all of the Inline Language Support
    Module's meta data in a file called "config". This file can be found in
    your "DIRECTORY" directory. If the file does not exist, Inline creates a
    new one. It will search your system for any module beginning with
    "Inline::". It will then call that module's "register()" method to get
    useful information for future invocations.

    Whenever you add a new ILSM, you should delete this file so that Inline
    will auto-discover your newly installed language module. (This should no
    longer be necessary as of Inline-0.49.)

CONFIGURATION OPTIONS
    This section lists all of the generic Inline configuration options. For
    language specific configuration, see the doc for that language.

    DIRECTORY
        The "DIRECTORY" config option is the directory that Inline uses to
        both build and install an extension.

        Normally Inline will search in a bunch of known places for a
        directory called '.Inline/'. Failing that, it will create a
        directory called '_Inline/'

        If you want to specify your own directory, use this configuration
        option.

        Note that you must create the "DIRECTORY" directory yourself. Inline
        will not do it for you.

    NAME
        You can use this option to set the name of your Inline extension
        object module. For example:

            use Inline C => 'DATA',
                       NAME => 'Foo::Bar';

        would cause your C code to be compiled in to the object:

            lib/auto/Foo/Bar/Bar.so
            lib/auto/Foo/Bar/Bar.inl

        (The .inl component contains dependency information to make sure the
        source code is in sync with the executable)

        If you don't use NAME, Inline will pick a name for you based on your
        program name or package name. In this case, Inline will also enable
        the AUTONAME option which mangles in a small piece of the MD5
        fingerprint into your object name, to make it unique.

    AUTONAME
        This option is enabled whenever the NAME parameter is not specified.
        To disable it say:

            use Inline C => 'DATA',
                       DISABLE => 'AUTONAME';

        AUTONAME mangles in enough of the MD5 fingerprint to make your
        module name unique. Objects created with AUTONAME will never get
        replaced. That also means they will never get cleaned up
        automatically.

        AUTONAME is very useful for small throw away scripts. For more
        serious things, always use the NAME option.

    VERSION
        Specifies the version number of the Inline extension object. It is
        used only for modules, and it must match the global variable
        $VERSION. Additionally, this option should used if (and only if) a
        module is being set up to be installed permanently into the Perl
        sitelib tree. Inline will croak if you use it otherwise.

        The presence of the VERSION parameter is the official way to let
        Inline know that your code is an installable*installed module.
        Inline will never generate an object in the temporary cache
        (_Inline* directory) if VERSION is set. It will also never try to
        recompile a module that was installed into someone's Perl site tree.

        So the basic rule is develop without VERSION, and deliver with
        VERSION.

    WITH
        "WITH" can also be used as a configuration option instead of using
        the special 'with' syntax. Do this if you want to use different
        sections of Inline code *with* different modules. (Probably a very
        rare usage)

            use Event;
            use Inline C => DATA => WITH => 'Event';

        Modules specified using the config form of "WITH" will not be
        automatically required. You must "use" them yourself.

    GLOBAL_LOAD
        This option is for compiled languages only. It tells Inline to tell
        DynaLoader to load an object file in such a way that its symbols can
        be dynamically resolved by other object files. May not work on all
        platforms. See the "GLOBAL" shortcut below.

    UNTAINT
        You can use this option whenever you use Perl's "-T" switch, for
        taint checking. This option tells Inline to blindly untaint all
        tainted variables. (This is generally considered to be an
        appallingly insecure thing to do, and not to be recommended - but
        the option is there for you to use if you want. Please consider
        using something other than Inline for scripts that need taint
        checking.) It also turns on SAFEMODE by default. See the "UNTAINT"
        shortcut below. You will see warnings about blindly untainting
        fields in both %ENV and Inline objects. If you want to silence these
        warnings, set the Config option NO_UNTAINT_WARN => 1. There can be
        some problems untainting Inline scripts where older versions of Cwd,
        such as those that shipped with early versions of perl-5.8 (and
        earlier), are installed. Updating Cwd will probably solve these
        problems.

    SAFEMODE
        Perform extra safety checking, in an attempt to thwart malicious
        code. This option cannot guarantee security, but it does turn on all
        the currently implemented checks. (Currently, the only "currently
        implemented check" is to ensure that the "DIRECTORY" option has also
        been used.)

        There is a slight startup penalty by using SAFEMODE. Also, using
        UNTAINT automatically turns this option on. If you need your code to
        start faster under "-T" (taint) checking, you'll need to turn this
        option off manually. Only do this if you are not worried about
        security risks. See the "UNSAFE" shortcut below.

    FORCE_BUILD
        Makes Inline build (compile) the source code every time the program
        is run. The default is 0. See the "FORCE" shortcut below.

    BUILD_NOISY
        Tells ILSMs that they should dump build messages to the terminal
        rather than be silent about all the build details.

    BUILD_TIMERS
        Tells ILSMs to print timing information about how long each build
        phase took. Usually requires "Time::HiRes".

    CLEAN_AFTER_BUILD
        Tells Inline to clean up the current build area if the build was
        successful. Sometimes you want to DISABLE this for debugging.
        Default is 1. See the "NOCLEAN" shortcut below.

    CLEAN_BUILD_AREA
        Tells Inline to clean up the old build areas within the entire
        Inline DIRECTORY. Default is 0. See the "CLEAN" shortcut below.

    PRINT_INFO
        Tells Inline to print various information about the source code.
        Default is 0. See the "INFO" shortcut below.

    PRINT_VERSION
        Tells Inline to print Version info about itself. Default is 0. See
        the "VERSION" shortcut below.

    REPORTBUG
        Puts Inline into 'REPORTBUG' mode, which is what you want if you
        desire to report a bug.

    REWRITE_CONFIG_FILE
        Default is 0, but setting 'REWRITE_CONFIG_FILE => 1' will mean that
        the existing configuration file in the Inline DIRECTORY will be
        overwritten. (This is useful if the existing config file is not up
        to date as regards supported languages.)

    WARNINGS
        This option tells Inline whether to print certain warnings. Default
        is 1.

INLINE CONFIGURATION SHORTCUTS
    This is a list of all the shortcut configuration options currently
    available for Inline. Specify them from the command line when running
    Inline scripts.

          perl -MInline=NOCLEAN inline_script.pl

    or

          perl -MInline=Info,force,NoClean inline_script.pl

    You can specify multiple shortcuts separated by commas. They are not
    case sensitive. You can also specify shortcuts inside the Inline program
    like this:

          use Inline 'Info', 'Force', 'Noclean';

    NOTE: If a 'use Inline' statement is used to set shortcuts, it can not
    be used for additional purposes.

    CLEAN
        Tells Inline to remove any build directories that may be lying
        around in your build area. Normally these directories get removed
        immediately after a successful build. Exceptions are when the build
        fails, or when you use the NOCLEAN or REPORTBUG options.

    FORCE
        Forces the code to be recompiled, even if everything is up to date.

    GLOBAL
        Turns on the GLOBAL_LOAD option.

    INFO
        This is a very useful option when you want to know what's going on
        under the hood. It tells Inline to print helpful information to
        "STDERR". Among the things that get printed is a list of which
        Inline functions were successfully bound to Perl.

    NOCLEAN
        Tells Inline to leave the build files after compiling.

    NOISY
        Use the BUILD_NOISY option to print messages during a build.

    REPORTBUG
        Puts Inline into 'REPORTBUG' mode, which does special processing
        when you want to report a bug. REPORTBUG also automatically forces a
        build, and doesn't clean up afterwards. This is so that you can tar
        and mail the build directory to me. REPORTBUG will print exact
        instructions on what to do. Please read and follow them carefully.

        NOTE: REPORTBUG informs you to use the tar command. If your system
        does not have tar, please use the equivalent "zip" command.

    SAFE
        Turns SAFEMODE on. UNTAINT will turn this on automatically. While
        this mode performs extra security checking, it does not guarantee
        safety.

    SITE_INSTALL
        This parameter used to be used for creating installable Inline
        modules. It has been removed from Inline altogether and replaced
        with a much simpler and more powerful mechanism,
        "Inline::MakeMaker". See the section below on how to create modules
        with Inline.

    _TESTING
        Used internally by C/t*09parser.t and C*t*10callback.t(in the
        Inline::C test suite). Setting this option with Inline::C will mean
        that files named 'parser_id' and 'void_test' are created in the
        .*Inline_test directory, creating that directory if it doesn't
        already exist. The files (but not the .*Inline_test directory) are
        cleaned up by calling Inline::C::_testing_cleanup(). Also used by
        t*06rewrite_config.t to trigger a warning.

    TIMERS
        Turn on BUILD_TIMERS to get extra diagnostic info about builds.

    UNSAFE
        Turns SAFEMODE off. Use this in combination with UNTAINT for
        slightly faster startup time under "-T". Only use this if you are
        sure the environment is safe.

    UNTAINT
        Turn the UNTAINT option on. Used with "-T" switch. In terms of
        secure practices, this is definitely not a recommended way of
        dealing with taint checking, but it's the only option currently
        available with Inline. Use it at your own risk.

    VERSION
        Tells Inline to report its release version.

WRITING MODULES WITH INLINE
    Writing CPAN modules that use C code is easy with Inline. Let's say that
    you wanted to write a module called "Math::Simple". Start by using the
    following command:

        h2xs -PAXn Math::Simple

    This will generate a bunch of files that form a skeleton of what you
    need for a distributable module. (Read the h2xs manpage to find out what
    the options do) Next, modify the "Simple.pm" file to look like this:

        package Math::Simple;
        $VERSION = '1.23';

        use base 'Exporter';
        @EXPORT_OK = qw(add subtract);
        use strict;

        use Inline C => 'DATA',
                   VERSION => '1.23',
                   NAME => 'Math::Simple';

        # The following Inline->init() call is optional - see below for more info.
        #Inline->init();

        1;

        __DATA__

        =pod

        =cut

        __C__
        int add(int x, int y) {
          return x + y;
        }

        int subtract(int x, int y) {
          return x - y;
        }

    The important things to note here are that you must specify a "NAME" and
    "VERSION" parameter. The "NAME" must match your module's package name.
    The "VERSION" parameter must match your module's $VERSION variable and
    they must be of the form "/^\d\.\d\d$/".

    NOTE: These are Inline's sanity checks to make sure you know what you're
    doing before uploading your code to CPAN. They insure that once the
    module has been installed on someone's system, the module would not get
    automatically recompiled for any reason. This makes Inline based modules
    work in exactly the same manner as XS based ones.

    Finally, you need to modify the Makefile.PL. Simply change:

        use ExtUtils::MakeMaker;

    to

        use Inline::MakeMaker;

    And, in order that the module build work correctly in the cpan shell,
    add the following directive to the Makefile.PL's WriteMakefile():

        CONFIGURE_REQUIRES  =>  {
            'Inline::MakeMaker'     => 0.45,
            'ExtUtils::MakeMaker'   => 6.52,
        },

    This "CONFIGURE_REQUIRES" directive ensures that the cpan shell will
    install Inline on the user's machine (if it's not already present)
    before building your Inline-based module. Specifying of
    "ExtUtils::MakeMaker => 6.52," is optional, and can be omitted if you
    like. It ensures only that some harmless warnings relating to the
    "CONFIGURE_REQUIRES" directive won't be emitted during the building of
    the module. It also means, of course, that ExtUtils::Makemaker will
    first be updated on the user's machine unless the user already has
    version 6.52 or later.

    If the "Inline->init();" is not done then, having installed
    Math::Simple, a warning that "One or more DATA sections were not
    processed by Inline" will appear when (and only when) Math::Simple is
    loaded by a "require call. It's a harmless warning - and if you're
    prepared to live with it, then there's no need to make the
    "Inline->init();" call.

    When the person installing "Math::Simple" does a ""make"", the generated
    Makefile will invoke Inline in such a way that the C code will be
    compiled and the executable code will be placed into the "./blib"
    directory. Then when a ""make install"" is done, the module will be
    copied into the appropriate Perl sitelib directory (which is where an
    installed module should go).

    Now all you need to do is:

        perl Makefile.PL
        make dist

    That will generate the file "Math-Simple-0.20.tar.gz" which is a
    distributable package. (It will also generate some harmless warnings in
    relation to "CONFIGURE_REQUIRES" unless the version of your
    ExtUtils::MakeMaker is 6.52 or later.) That's all there is to it.

    IMPORTANT NOTE: Although the above steps will produce a workable module,
    you still have a few more responsibilities as a budding new CPAN author.
    You need to write lots of documentation and write lots of tests. Take a
    look at some of the better CPAN modules for ideas on creating a killer
    test harness. Actually, don't listen to me, go read these:

    *   perldoc perlnewmod

    *   <http://www.cpan.org/modules/04pause.html>

    *   <http://www.cpan.org/modules/00modlist.long.html>

HOW INLINE WORKS
    In reality, Inline just automates everything you would need to do if you
    were going to do it by hand (using XS, etc).

    Inline performs the following steps:

    *   Receive the Source Code

        Inline gets the source code from your script or module with a
        statements like the following: use Inline C => "Source-Code"; or use
        Inline; bind Inline C => "Source-Code"; where "C" is the programming
        language of the source code, and "Source- Code" is a string, a file
        name, an array reference, or the special 'DATA' keyword. Since
        Inline is coded in a ""use"" statement, everything is done during
        Perl's compile time. If anything needs to be done that will affect
        the "Source- Code", it needs to be done in a "BEGIN" block that is
        *before* the ""use Inline ..."" statement. If you really need to
        specify code to Inline at runtime, you can use the "bind()" method.
        Source code that is stowed in the 'DATA' section of your code, is
        read in by an "INIT" subroutine in Inline. That's because the "DATA"
        filehandle is not available at compile time.

    *   Check if the Source Code has been Built

        Inline only needs to build the source code if it has not yet been
        built. It accomplishes this seemingly magical task in an extremely
        simple and straightforward manner. It runs the source text through
        the "Digest::MD5" module to produce a 128-bit "fingerprint" which is
        virtually unique. The fingerprint along with a bunch of other
        contingency information is stored in a ".inl" file that sits next to
        your executable object. For instance, the "C" code from a script
        called "example.pl" might create these files: example_pl_3a9a.so
        example_pl_3a9a.inl If all the contingency information matches the
        values stored in the ".inl" file, then proceed to step 8. (No
        compilation is necessary)

    *   Find a Place to Build and Install

        At this point Inline knows it needs to build the source code. The
        first thing to figure out is where to create the great big mess
        associated with compilation, and where to put the object when it's
        done. By default Inline will try to build and install under the
        first place that meets one of the following conditions: A) The
        DIRECTORY= config option; if specified B) The PERL_INLINE_DIRECTORY
        environment variable; if set C) .Inline/ (in current directory); if
        exists and $PWD != $HOME D) bin/.Inline/ (in directory of your
        script); if exists E) ~/.Inline/; if exists F) ./_Inline/; if exists
        G) bin/_Inline; if exists H) Create ./_Inline/; if possible I)
        Create bin/_Inline/; if possible Failing that, Inline will croak.
        This is rare and easily remedied by just making a directory that
        Inline will use. If the PERL_INSTALL_ROOT Environment Variable has
        been set, you will need to make special provision for that if the
        'make install' phase of your Inline scripts are to succeed. If the
        module option is being compiled for permanent installation, then
        Inline will only use "./_Inline/" to build in, and the
        $Config{installsitearch} directory to install the executable in.
        This action is caused by Inline::MakeMaker, and is intended to be
        used in modules that are to be distributed on the CPAN, so that they
        get installed in the proper place.

    *   Parse the Source for Semantic Cues

        Inline::C uses the module "Parse::RecDescent" to parse through your
        chunks of C source code and look for things that it can create
        run-time bindings to. In "C" it looks for all of the function
        definitions and breaks them down into names and data types. These
        elements are used to correctly bind the "C" function to a "Perl"
        subroutine. Other Inline languages like Python and Java actually use
        the "python" and "javac" modules to parse the Inline code.

    *   Create the Build Environment

        Now Inline can take all of the gathered information and create an
        environment to build your source code into an executable. Without
        going into all the details, it just creates the appropriate
        directories, creates the appropriate source files including an XS
        file (for C) and a "Makefile.PL".

    *   Build the Code and Install the Executable

        The planets are in alignment. Now for the easy part. Inline just
        does what you would do to install a module. "`perl Makefile.PL &&
        make && make test && make install>". If something goes awry, Inline
        will croak with a message indicating where to look for more info.

    *   Tidy Up

        By default, Inline will remove all of the mess created by the build
        process, assuming that everything worked. If the build fails, Inline
        will leave everything intact, so that you can debug your errors.
        Setting the "NOCLEAN" shortcut option will also stop Inline from
        cleaning up.

    *   DynaLoad the Executable

        For C (and C++), Inline uses the "DynaLoader::bootstrap" method to
        pull your external module into "Perl" space. Now you can call all of
        your external functions like Perl subroutines. Other languages like
        Python and Java, provide their own loaders.

SEE ALSO
    For information about using Inline with C see Inline::C.

    For sample programs using Inline with C see Inline::C-Cookbook.

    For "Formerly Answered Questions" about Inline, see Inline-FAQ.

    For information on supported languages and platforms see Inline-Support.

    For information on writing your own Inline Language Support Module, see
    Inline-API.

    Inline's mailing list is inline@perl.org

    To subscribe, send email to inline-subscribe@perl.org

BUGS AND DEFICIENCIES
    When reporting a bug, please do the following:

    *   Put "use Inline REPORTBUG;" at the top of your code, or use the
        command line option "perl -MInline=REPORTBUG ...".

    *   Run your code.

    *   Follow the printed directions.

AUTHOR
    Ingy döt Net <ingy@cpan.org>

    Sisyphus <sisyphus@cpan.org> fixed some bugs and is current
    co-maintainer.

COPYRIGHT
    *   Copyright 2000-2014. Ingy döt Net.

    *   Copyright 2008, 2010-2014. Sisyphus.

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

    See <http://www.perl.com/perl/misc/Artistic.html>

