php-src/README.SELF-CONTAINED-EXTENSIONS
2000-05-02 21:51:48 +00:00

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$Id$
=============================================================================
HOW TO CREATE A SELF-CONTAINED PHP EXTENSION
A self-contained extension can be distributed independently of
the PHP source. To create such an extension, three things are
required:
- Makefile template (Makefile.in)
- Configuration file (config.m4)
- Source code for your module
We will describe now how to create these and how to put things
together.
CONVERTING AN EXISTING EXTENSION
Just to show you how easy it is to create a self-contained
extension, we will convert an embedded extension into a
self-contained one. Install PHP and execute the following
commands.
$ mkdir /tmp/newext
$ cd /tmp/newext
You now have an empty directory. We will copy the files from
the mysql extension:
$ cp -rp php-4.0.X/ext/mysql/* .
It is time to finish the module. Run:
$ phpize
You can now ship the contents of the directory - the extension
can live completely on its own.
The user instructions boil down to
$ ./configure \
[--with-php-config=/path/to/php-config] \
[--with-mysql=MYSQL-DIR]
$ make install
The MySQL module will either use the embedded MySQL client
library or the MySQL installation in MYSQL-DIR.
DEFINING THE NEW EXTENSION
Our demo extension is called "foobar".
It consists of two source files "foo.c" and "bar.c"
(and any arbitrary amount of header files, but that is not
important here).
The demo extension does not reference any external
libraries (that is important, because the user does not
need to specify anything).
CREATING THE MAKEFILE TEMPLATE
The Makefile Template (Makefile.in) contains three lines:
------------------------------------------------------------------------------
LTLIBRARY_SHARED_NAME = foobar.la
LTLIBRARY_SOURCES = foo.c bar.c
include $(top_srcdir)/build/rules.mk
------------------------------------------------------------------------------
LTLIBRARY_SHARED_NAME specifies the name of the extension.
It must be of the form `ext-name.la'.
LTLIBRARY_SOURCES specifies the names of the sources files. You can
name an arbitrary number of source files here.
The final include directive includes the build rules (you usually
don't need to care about what happens there). rules.mk and other
files are installed by phpize which we will cover later.
CREATING THE M4 CONFIGURATION FILE
The m4 configuration can perform additional checks. For a
self-contained extension, you do not need more than a few
macro calls.
------------------------------------------------------------------------------
PHP_ARG_ENABLE(foobar,whether to enable foobar,
[ --enable-foobar Enable foobar])
PHP_EXTENSION(foobar, $ext_shared)
------------------------------------------------------------------------------
PHP_ARG_ENABLE will automatically set the correct variables, so
that the extension will be enabled by PHP_EXTENSION in shared mode.
CREATING SOURCE FILES
[You are currently alone here. There are a lot of existing modules,
use a simply module as a starting point and add your own code.]
CREATING THE SELF-CONTAINED EXTENSION
Put Makefile.in, config.m4 and the source files into one directory.
Then run phpize (this is installed during make install by PHP 4.0).
For example, if you configured PHP with --prefix=/php, you would run
$ /php/bin/phpize
This will automatically copy the necessary build files and create
configure from your config.m4.
And that's it. You now have a self-contained extension.
INSTALLING A SELF-CONTAINED EXTENSION
An extension can be installed by running:
$ ./configure \
[--with-php-config=/path/to/php-config]
$ make install