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<title>The ext_skel script</title>
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<h2 class="title">The ext_skel script</h2>
<p class="para">
A PHP extension is composed of several files common to all extensions. As
the details of many of those files are similar from extension to extension,
it can be laborious to duplicate the content for each one. Fortunately, there
is a script which can do all of the initial setup for you. It's called
<strong class="command">ext_skel</strong>, and it's been distributed with PHP since 4.0.
</p>
<p class="para">
Running <strong class="command">ext_skel</strong> with no parameters produces this
output in PHP 5.2.2:
<div class="example-contents screen">
<div class="cdata"><pre>
php-5.2.2/ext$ ./ext_skel
./ext_skel --extname=module [--proto=file] [--stubs=file] [--xml[=file]]
[--skel=dir] [--full-xml] [--no-help]
--extname=module module is the name of your extension
--proto=file file contains prototypes of functions to create
--stubs=file generate only function stubs in file
--xml generate xml documentation to be added to phpdoc-cvs
--skel=dir path to the skeleton directory
--full-xml generate xml documentation for a self-contained extension
(not yet implemented)
--no-help don't try to be nice and create comments in the code
and helper functions to test if the module compiled
</pre></div></div>
Generally, when developing a new extension the only parameters you will be
interested in are <em>--extname</em> and
<em>--no-help</em>. Unless you are already experienced with the
structure of an extension, you will <em class="emphasis">not</em> want to use
<em>--no-help</em>; specifying it causes
<strong class="command">ext_skel</strong> to leave out many helpful comments in the
files it generates.
</p>
<p class="para">
This leaves you with <em>--extname</em>, which tells
<strong class="command">ext_skel</strong> what the name of your extension is. This
"name" is an all-lowercase identifier containing only letters and
underscores which is unique among everything in the
<var class="filename">ext/</var> folder of your PHP distribution.
</p>
<p class="para">
The <em>--proto</em> option is intended to allow the developer to
specify a header file from which a set of PHP functions will be created,
ostensibly for the purpose of developing an extension based on a library,
but it often functions poorly with most modern header files. A test run on
the <var class="filename">zlib.h</var> header resulted in a very large number of
empty and nonsense prototypes in the <strong class="command">ext_skel</strong> output
files. The <em>--xml</em> and <em>--full-xml</em>
options are entirely nonfunctional thus far. The <em>--skel</em>
option can be used to specify a modified set of skeleton files to work from,
a topic which is beyond the scope of this section.
</p>
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