Getting started with writing PHP extensions

This article explains how PHP extensions are written by writing a simple PHP extension hello_world. This extension has no practicality and is purely used to learn how to write extensions. If you really want to write a practical PHP extension yourself, you need to be familiar with the ZEND API and have high requirements for C language.

Okay, let’s get to the point.

1. Enter the ext directory of the PHP source code, and then execute:

<code><span>./ext_skel --extname</span>=<span>hello_world</span></code>

2. Enter the hello_world directory, edit config.m4, and remove the dnl in front of lines 16, 18 and 53:

<code><span>PHP_ARG_ENABLE</span>(<span>hello_world</span>, <span>whether</span><span>to</span><span>enable</span><span>hello_world</span><span>support</span>,
<span>[  --enable-hello_world           Enable hello_world support]</span>)
<span>AC_DEFINE</span>(<span>HAVE_HELLO_WORLDLIB</span>,1,<span>[ ]</span>)
</code>

3. Modify php_hello_world. h file, change the original

<code><span>#<span>define</span> PHP_HELLO_WORLD_H</span></code>

to the following content:

<code><span>#<span>define</span> PHP_HELLO_WORLD_H 1</span><span>#<span>define</span> PHP_HELLO_WORLD_VERSION "1.0"</span><span>#<span>define</span> PHP_HELLO_WORLD_EXTNAME "hello_world"</span>
PHP_FUNCTION(hello_world);<span>//这句最关键</span></code>

4. Modify the hello_world.c file:
Change the following content:

<code><span>const</span> zend_function_entry hello_world_functions[] = {
        PHP_FE(confirm_hello_world_compiled,    <span>NULL</span>)           <span>/* For testing, remove later. */</span>
        PHP_FE_END      <span>/* Must be the last line in hello_world_functions[] */</span>
};</code>

to:

<code><span>const</span> zend_function_entry hello_world_functions[] = {
        PHP_FE(confirm_hello_world_compiled,    <span>NULL</span>)           <span>/* For testing, remove later. */</span>        PHP_FE(hello_world,    <span>NULL</span>)
        PHP_FE_END      <span>/* Must be the last line in hello_world_functions[] */</span>
};
</code>

Then add the following content at the end:

<code><span>//扩展函数正文部分</span><span>PHP_FUNCTION(hello_world)</span>{
        <span>RETURN_STRING(<span>"Hello World!"</span>,<span>1</span>)</span>;
}</code>

5. Go to the ext/hello_world directory and execute the following command

<code>/usr/<span>local</span>/php/bin/phpize
<span>.</span>/configure <span>--</span><span>with</span><span>-php</span><span>-config</span><span>=</span>/usr/<span>local</span>/php/bin/php<span>-config</span>
make <span>&&</span> make install
</code>

6. Edit php.ini and add the following content:

<code><span>extension</span>=<span>hello_world.so</span></code>

Test:
Execute the following content on the command line:

<code>php <span>-r</span><span>"echo hello_world();"</span></code>

At this time, you will see the following content on the standard output:

<code><span>Hello</span><span>World</span><span>!</span></code>

At this point, the hello_world extension is written!

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The above introduces the introduction to writing PHP extensions, including aspects of content. I hope it will be helpful to friends who are interested in PHP tutorials.