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 uses ExtUtils::Depends version 0.400 or higher, your
module only needs this:
package Module;
use autouse Module::Install::Files => qw(Inline);
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.
using
You can override modules that get used by ILSMs with the "using"
option. This is typically used to override the default parser for
Inline::C, but might be used by any ILSM for any purpose.
use Inline config => using => '::Parser::RecDescent';
use Inline C => '...';
This would tell Inline::C to use Inline::C::Parser::RecDescent.
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>