How to write a standalone PHP extension_PHP Tutorial

How to write a standalone PHP extension

Stand-alone PHP extensions can be distributed independently of the PHP source code. To create such an extension, you need to have two things ready:

• Configuration file (config.m4)

• Your module source code

Next we describe how to create and combine these files.

Prepare system tools

If you want the extension to be compiled and run successfully on the system, you need to prepare the following tools:

• GNU autoconf

• GNU automake

• GNU libtool

• GNU m4

The above can be obtained from ftp://ftp.gnu.org/pub/gnu/.

Note: The above are tools that can only be used in a Unix-like environment.

Modify an existing extension

To show how easy it is to create a standalone extension, let's first convert an extension that is already embedded into PHP into a standalone extension. Install PHP and execute the following command:

$ mkdir /tmp/newext
$ cd /tmp/newext

Now you have an empty directory. We copy the files in the mysql extension directory:

$ cp -rp php-4.0.X/ext/mysql/* .
# Note: It seems that this README really needs to be updated
# The mysql extension has been removed from PHP7

The expansion is complete here, execute:

$phpize

Now you can store the files in this directory anywhere independently, and this extension can exist completely independently.

Users need to use the following commands when compiling:

$ ./configure
[--with-php-config=/path/to/php-config]
        [--with-mysql=MYSQL-DIR]
$ make install

This allows the MySQL module to use the embedded MySQL client library or the installed MySQL located in the MySQL directory.

Note: This means that if you want to write a PHP extension, you need to have PHP installed and download a copy of the PHP source code.

Define a new extension

Let’s name the example extension “foobar”.

The new extension contains two resource files: foo.c and bar.c and some header files, but these are not only important).

It is important that the example extension does not reference any external libraries, because then the user does not need to specify some compilation options).

The

LTLIBRARY_SOURCES option is used to specify the name of the resource file. You can have any number of resource files.

Note: The above mentioned are the configuration options in the Makefile.in file, please refer to xdebug.

Modify the configuration file of m4 suffix

The m4 configuration file can specify some additional checks. For a standalone extension, you only need to make 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 to ensure that the extension can be PHP_NEW_EXTENSION launched in shared mode.

The first parameter of

PHP_NEW_EXTENSION is the name of the extension, and the second parameter is the resource file. The third parameter $ext_shared is set by PHP_ARG_ENABLE/WITH for PHP_NEW_EXTENSION.

Always use PHP_ARG_ENABLE or PHP_ARG_WITH for settings. Even if you don't plan to publish your PHP module, these settings ensure that your module's interface with the main PHP module remains consistent.

Note: PHP_ARG_ENABLE and PHP_ARG_WITH should be used to define whether the module is dynamically extended or statically compiled into PHP, just like the --enable-xxx and --with-xxx used when compiling PHP.

Create resource file

ext_skel You can create some generic code for your PHP module, and you can also write some basic function definitions and C code to handle the function parameters. Specific information can be found in READNE.EXT_SKEL.

Don’t worry there are no examples, there are many modules in PHP for you to refer to, choose a simple point to start and add your own code.

Note: ext_skel The resource files and configuration files required by the basic module can be generated, and there is no need to create them yourself.

Modify custom module

Put the config.m4 file and resource files in the same directory, and then execute phpize PHP 4.0 and above have phpize installed when compiling PHP).

If your phpize is not in the system environment variable, you need to specify the absolute path, for example:

$ /php/bin/phpize

This command will automatically copy the necessary build files to the current directory and create a configuration file based on config.m4.

After following the above steps, you already have an independent extension.

Install extension

The extension can be compiled and installed through the following command:

$ ./configure
              [--with-php-config=/path/to/php-config]
$ make install

Add sharing support to the module

Sometimes independent extensions need to be shared for other modules to load. Next I will explain how to add sharing support to the already created foo module.

#ifdef COMPILE_DL_FOO
ZEND_GET_MODULE(foo)
#endif

This paragraph has been mentioned above, and I just emphasize it again here.

PECL website agreement

If you plan to publish your website extending to PECL, there are a few things to consider:

#define PHP_FOO_VERSION "1.2.3"

http://www.bkjia.com/PHPjc/1089382.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/1089382.htmlTechArticleHow to write an independent PHP extension Independent PHP extensions can be distributed independently of the PHP source code. To create such an extension, you need to prepare two things: Configuration file...