After reading some of the content mentioned in the preface, you should have a general understanding of PHP extension development. Some people may think that developing extensions is troublesome and complicated. In fact, it is not. In this article, we will quickly explain Get into character and develop our first extension.
1. Compile PHP
Before development, you need to prepare the PHP source code and compile it. The process is as follows:
<span tar</span> -zxvf php-<span 5.3</span>.<span 9</span>.<span tar</span><span .gz cd php</span>-<span 5.3</span>.<span 9</span>
I am using php5.3.9. After decompression, we entered the PHP source directory, then we directly compiled and added php.ini:
./configure --prefix=/usr/local/webserver/php --enable-fastcgi --enable-fpm --enable-<span debug </span><span make</span> && <span make</span> <span install</span> <span cp</span> /home/soft/php-<span 5.3</span>.<span 9</span>/php.ini-development /usr/local/webserver/php/lib/php.ini
Compilation is completed. I did not statically compile other extensions, but enabled debugging, which will be used later. Then modify the corresponding items in php.ini, which I won’t go into detail here.
Now add PHP related environment variables to save a lot of work later:
vim /root/.bash_profile
I use root, and other different users modify the .bask_profile file in the corresponding user directory, and add: /usr/local/webserver/php/bin/ after the PATH in the file, similar to the following:
PATH=$PATH:$HOME/bin:/usr/local/webserver/php/bin/
Environment variables are set, let’s check the PHP version:
OK, the compilation is completed, let us continue.
2. Typical development process
A typical extension development process is as follows:
3. Extended function definition
-2147483648 to 2147483647, same as 32-bit systems.
4. Formal development
cd /home/soft/php-<span 5.3</span>.<span 9</span>/ext
Then learn about the extended skeleton tool ext_skel provided by PHP to generate a skeleton. The usage of ext_skel is as follows:
./ext_skel --extname=module [--proto=<span file</span>] [--stubs=<span file</span>] [--xml[=<span file</span><span ]]
[</span>--skel=<span dir</span>] [--full-xml] [--no-<span help]
</span>--extname=<span module module is the name of your extension（模块名，会在当前目录创建一个该名称子目录）
</span>--proto=<span file</span> <span file</span><span contains prototypes of functions to create（函数原型定义文件）
</span>--stubs=<span file</span> generate only <span function</span> stubs <span in</span> <span file</span>
--xml generate xml documentation to be added to phpdoc-<span cvs
</span>--skel=<span dir</span> path to the skeleton directory(设置骨架生成的目录，不设置该项则默认在ext/<span extname下)
</span>--full-xml generate xml documentation <span for</span> a self-<span contained extension
(not yet implemented)
</span>--no-help don<span '</span><span t try to be nice and create comments in the code</span>
and helper functions to test <span if</span> the module compiled (生成的代码中不显示各种帮助注释)This time we are going to use two options, --extname=myip is to define the name of the extension, and --proto=myip.pro is to define the function prototype of the extension. First we generate the extension function prototype file:
vim myip.pro
Add the following:
<span int</span> ip2long32(<span string</span> ip)
This means that there is a function in our extension that returns an int and takes a string as input.
At this time, execute the following command to generate the extended skeleton:
./ext_skel --extname=myip --proto=myip.pro
OK, at this time you will find that a subdirectory myip is generated under the current PHP extension directory. Enter myip and take a look:
<span cd myip ll</span>
You will find a bunch of files generated, as shown below:
At this point we can proceed to the second step.
2. Modify config.m4
Regarding the function of the config.m4 file, we will leave it to a later article to explain in detail. Now we only explain what to do.
Use vim to edit config.m4:
vim config.m4
Remove the dnl at the beginning of lines 16 to 18, as follows:
The specific reasons for doing this will be explained in a later article. Here we directly exit and save config.m4 and continue to the next step.
3. Encoding
The main event is here, you can finally enter myip.c to code functions, let’s cheer together!
vim myip.c
Find the location shown in the picture below:
The picture shows the corresponding function generated by the extended skeleton tool based on the function prototype we provided. There are several things to note here:
1. PHP_FUNCTION: It is a macro defined by PHP core. It is the same as ZEND_FUNCTION and is used to define extension functions. The actual generated function name is zif_ip2long32.
2. zend_parse_parameters: Since PHP is a weakly typed language and C is a strongly typed language, this function needs to be used to receive the parameters passed in by PHP and perform certain type conversions to convert PHP variables into C language. Type of identification.
The prototype of zend_parse_parameters function is as follows:
zend_parse_parameters(<span int</span> num_args TSRMLS_CC, <span char</span> *type_spec, …);
Parameter description:
type_spec是格式化字符串，其常见的含义如下：
参数 代表着的类型
b Boolean
l Integer 整型
d Floating point 浮点型
s String 字符串
r Resource 资源
a Array 数组
o Object instance 对象
O Object instance of a specified type 特定类型的对象
z Non-specific zval 任意类型～
Z zval**类型
f 表示函数、方法名称
我们将该函数修改为如下内容：
<span PHP_FUNCTION(ip2long32)
{
</span><span char</span> *ip =<span NULL;
</span><span int</span> argc =<span ZEND_NUM_ARGS();
</span><span int</span><span ip_len;
</span><span if</span> (zend_parse_parameters(argc TSRMLS_CC, <span "</span><span s</span><span "</span>, &ip, &ip_len) ==<span FAILURE) {
</span><span return</span><span ;
}
int32_t ip_int32;
unsigned </span><span char</span><span ip1, ip2, ip3, ip4;
sscanf(ip, </span><span "</span><span %hhu.%hhu.%hhu.%hhu</span><span "</span>, &ip1, &ip2, &ip3, &<span ip4);
ip_int32 </span>= (int32_t)((ip1 << <span 24</span>) | (ip2 << <span 16</span>) | (ip3 << <span 8</span>) |<span ip4);
RETURN_LONG(ip_int32);
}</span>功能完成了，这边有个RETURN_LONG(ip_int32)比较特殊，这也是PHP内核提供的宏，用于返回值给PHP，具体说明如下：
设置返回值并且结束函数 设置返回值 宏返回类型和参数
RETURN_LONG(l) RETVAL_LONG(l) 整数
RETURN_BOOL(b) RETVAL_BOOL(b) 布尔数(1或0)
RETURN_NULL() RETVAL_NULL() NULL
RETURN_DOUBLE(d) RETVAL_DOUBLE(d) 浮点数
RETURN_STRING(s, dup) RETVAL_STRING(s, dup) 字符串。如果dup为1，引擎会调用estrdup()重复s，使用拷贝。如果dup为0，就使用s
RETURN_STRINGL(s, l, dup) RETVAL_STRINGL(s, l, dup) 长度为l的字符串值。与上一个宏一样，但因为s的长度被指定，所以速度更快。
RETURN_TRUE RETVAL_TRUE 返回布尔值true。注意到这个宏没有括号。
RETURN_FALSE RETVAL_FALSE 返回布尔值false。注意到这个宏没有括号。
RETURN_RESOURCE(r) RETVAL_RESOURCE(r) 资源句柄。
编码完成了，保存并退出，然后我们可以开始编译了。
4. 编译
<span phpize .</span>/configure --with-php-config=/usr/local/webserver/php/bin/php-<span config </span><span make</span> && <span make</span> <span install</span>
不出意外的话编译完成后会有如下提示：
Installing shared extensions: /usr/local/webserver/php/lib/php/extensions/debug-non-zts-<span 20090626</span>/
进入该目录看下是否已经有myip.so，有的话最后我们就可以修改php.ini载入该so文件
5. 修改php.ini
cd /usr/local/webserver/php/<span lib vim php.ini</span>
修改extension_dir，并加入 extension = myip.so
extension_dir = "/usr/local/webserver/php/lib/php/extensions/debug-non-zts-20090626/"<span extension </span>= myip.so
退出保存，并重启php，如果是使用Phpfpm的话可以执行如下命令：
<span kill</span> -USR2 `<span cat</span> /usr/local/webserver/php/var/run/php-fpm.pid`
看下扩展是否正常载入：
[root@tm977 lib]# php -m|<span grep</span><span myip myip</span>
说明已经正常载入了，最后我们测试下扩展函数吧！
6. 测试
php -r <span "</span><span var_dump(ip2long32('192.168.1.1'));</span><span "</span>
<span int</span>(-<span 1062731519</span><span )
php </span>-r <span "</span><span var_dump(ip2long('192.168.1.1'));</span><span "</span>
<span int</span>(<span 3232235777</span>)如上所示，ip2long32输出的是32位有符号整数，而ip2long输出的是64位无符号整数，大功告成！
五、小结
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
