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- 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, two things are
- required:
- - Configuration file (config.m4)
- - Source code for your module
- We will describe now how to create these and how to put things
- together.
- PREPARING YOUR SYSTEM
- While the result will run on any system, a developer's setup needs these
- tools:
- GNU autoconf
- GNU automake
- GNU libtool
- GNU m4
- All of these are available from
- ftp://ftp.gnu.org/pub/gnu/
- 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).
- LTLIBRARY_SOURCES specifies the names of the sources files. You can
- name an arbitrary number of source files here.
- 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])
- if test "$PHP_FOOBAR" != "no"; then
- PHP_NEW_EXTENSION(foobar, foo.c bar.c, $ext_shared)
- fi
- ------------------------------------------------------------------------------
- PHP_ARG_ENABLE will automatically set the correct variables, so
- that the extension will be enabled by PHP_NEW_EXTENSION in shared mode.
- The first argument of PHP_NEW_EXTENSION describes the name of the
- extension. The second names the source-code files. The third passes
- $ext_shared which is set by PHP_ARG_ENABLE/WITH to PHP_NEW_EXTENSION.
- Please use always PHP_ARG_ENABLE or PHP_ARG_WITH. Even if you do not
- plan to distribute your module with PHP, these facilities allow you
- to integrate your module easily into the main PHP module framework.
- CREATING SOURCE FILES
- ext_skel can be of great help when creating the common code for all modules
- in PHP for you and also writing basic function definitions and C code for
- handling arguments passed to your functions. See README.EXT_SKEL for further
- information.
- As for the rest, you are currently alone here. There are a lot of existing
- modules, use a simple module as a starting point and add your own code.
- CREATING THE SELF-CONTAINED EXTENSION
- Put 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
- ADDING SHARED MODULE SUPPORT TO A MODULE
- In order to be useful, a self-contained extension must be loadable
- as a shared module. I will explain now how you can add shared module
- support to an existing module called foo.
- 1. In config.m4, use PHP_ARG_WITH/PHP_ARG_ENABLE. Then you will
- automatically be able to use --with-foo=shared[,..] or
- --enable-foo=shared[,..].
- 2. In config.m4, use PHP_NEW_EXTENSION(foo,.., $ext_shared) to enable
- building the extension.
- 3. Add the following lines to your C source file:
- #ifdef COMPILE_DL_FOO
- ZEND_GET_MODULE(foo)
- #endif
- PECL SITE CONFORMITY
- If you plan to release an extension to the PECL website, there are several
- points to be regarded.
- 1. Add LICENSE or COPYING to the package.xml
- 2. The following should be defined in one of the extension header files
- #define PHP_FOO_VERSION "1.2.3"
- This macros has to be used within your foo_module_entry to indicate the
- extension version.
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