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175 lines
5.1 KiB
Plaintext
175 lines
5.1 KiB
Plaintext
$Id$
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=============================================================================
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HOW TO CREATE A SELF-CONTAINED PHP EXTENSION
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A self-contained extension can be distributed independently of
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the PHP source. To create such an extension, three things are
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required:
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- Makefile template (Makefile.in)
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- Configuration file (config.m4)
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- Source code for your module
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We will describe now how to create these and how to put things
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together.
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PREPARING YOUR SYSTEM
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While the result will run on any system, a developer's setup needs these
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tools:
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GNU autoconf
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GNU automake
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GNU libtool
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GNU m4
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All of these are available from
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ftp://ftp.gnu.org/pub/gnu/
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CONVERTING AN EXISTING EXTENSION
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Just to show you how easy it is to create a self-contained
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extension, we will convert an embedded extension into a
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self-contained one. Install PHP and execute the following
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commands.
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$ mkdir /tmp/newext
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$ cd /tmp/newext
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You now have an empty directory. We will copy the files from
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the mysql extension:
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$ cp -rp php-4.0.X/ext/mysql/* .
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It is time to finish the module. Run:
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$ phpize
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You can now ship the contents of the directory - the extension
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can live completely on its own.
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The user instructions boil down to
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$ ./configure \
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[--with-php-config=/path/to/php-config] \
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[--with-mysql=MYSQL-DIR]
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$ make install
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The MySQL module will either use the embedded MySQL client
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library or the MySQL installation in MYSQL-DIR.
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DEFINING THE NEW EXTENSION
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Our demo extension is called "foobar".
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It consists of two source files "foo.c" and "bar.c"
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(and any arbitrary amount of header files, but that is not
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important here).
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The demo extension does not reference any external
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libraries (that is important, because the user does not
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need to specify anything).
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CREATING THE MAKEFILE TEMPLATE
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The Makefile Template (Makefile.in) contains three lines:
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------------------------------------------------------------------------------
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LTLIBRARY_SHARED_NAME = foobar.la
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LTLIBRARY_SOURCES = foo.c bar.c
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include $(top_srcdir)/build/dynlib.mk
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------------------------------------------------------------------------------
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LTLIBRARY_SHARED_NAME specifies the name of the extension.
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It must be of the form `ext-name.la'.
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LTLIBRARY_SOURCES specifies the names of the sources files. You can
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name an arbitrary number of source files here.
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The final include directive includes the build rules (you usually
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don't need to care about what happens there). rules.mk and other
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files are installed by phpize which we will cover later.
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CREATING THE M4 CONFIGURATION FILE
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The m4 configuration can perform additional checks. For a
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self-contained extension, you do not need more than a few
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macro calls.
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------------------------------------------------------------------------------
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PHP_ARG_ENABLE(foobar,whether to enable foobar,
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[ --enable-foobar Enable foobar])
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if test "$PHP_FOOBAR" != "no"; then
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PHP_EXTENSION(foobar, $ext_shared)
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fi
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------------------------------------------------------------------------------
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PHP_ARG_ENABLE will automatically set the correct variables, so
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that the extension will be enabled by PHP_EXTENSION in shared mode.
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Please use always PHP_ARG_ENABLE or PHP_ARG_WITH. Even if you do not
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plan to distribute your module with PHP, these facilities allow you
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to integrate your module easily into the main PHP module framework.
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CREATING SOURCE FILES
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ext_skel can be of great help when creating the common code for all modules
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in PHP for you and also writing basic function definitions and C code for
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handling arguments passed to your functions. See README.EXT_SKEL for further
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information.
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As for the rest, you are currently alone here. There are a lot of existing
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modules, use a simple module as a starting point and add your own code.
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CREATING THE SELF-CONTAINED EXTENSION
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Put Makefile.in, config.m4 and the source files into one directory.
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Then run phpize (this is installed during make install by PHP 4.0).
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For example, if you configured PHP with --prefix=/php, you would run
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$ /php/bin/phpize
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This will automatically copy the necessary build files and create
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configure from your config.m4.
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And that's it. You now have a self-contained extension.
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INSTALLING A SELF-CONTAINED EXTENSION
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An extension can be installed by running:
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$ ./configure \
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[--with-php-config=/path/to/php-config]
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$ make install
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ADDING SHARED MODULE SUPPORT TO A MODULE
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In order to be useful, a self-contained extension must be loadable
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as a shared module. I will explain now how you can add shared module
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support to an existing module called foo.
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1. In config.m4, use PHP_ARG_WITH/PHP_ARG_ENABLE. Then you will
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automatically be able to use --with-foo=shared or
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--enable-foo=shared.
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2. In config.m4, use PHP_EXTENSION(foo, $ext_shared) to enable
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building the extension.
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3. Add the following line to Makefile.in:
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LTLIBRARY_SHARED_NAME = foo.la
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4. Add the following lines to your C source file:
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#ifdef COMPILE_DL_FOO
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ZEND_GET_MODULE(foo)
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#endif
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