Write the first PHP extension to calculate the number of arrays

Requirements: Write the first PHP extension, which contains a function called maxwelldu. maxwelldu can calculate the length of an array (same as count)

Requirements: Understand C/C++ programming and be familiar with PHP programming

System: CentOS6.5

Environment: LNMP (yum installation)

To take the first step and start writing PHP extensions, we will use a tool, and this tool is in the PHP source code, so we download a PHP source code, http://php.net /downloads.php

cd ~
mkdir software
cd software
wget http://cn2.php.net/distributions/php-5.6.11.tar.gz
tar zxvf php-5.6.11.tar.gz
cd php-5.6.11/ext

#Create an extension project. After the creation is completed, there will be an additional sayhello folder in the ext directory. This folder is our extension project

./ext_skel --extname=maxwelldu
cd maxwelldu
vim config.m4

#Open permission and remove the dnl and [ before the PHP_ARG_ENABLE line. --enable-maxwelldu ] The dnl in front of this line

PHP_ARG_ENABLE(maxwelldu, whether to enable maxwelldu support,
dnl Make sure that the comment is aligned:
[  --enable-maxwelldu           Enable maxwelldu support])

#Add

vim php_maxwelldu.h

PHP_FUNCTION(maxwelldu);

at the end of the file #Add

vim maxwelldu.c
```
PHP_FUNCTION(maxwelldu){
        zval *arr;               //声明一个变量来接受数组参数
        HashTable *arr_hash;    //声明一个HashTable的变量
        int array_count;        //声明一个数组长度的变量
        if(zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &arr)==FAILURE){ //判断接受的数组是>否是数组, 并把值放入arr中
                return;
        }
        arr_hash = Z_ARRVAL_P(arr); //将数组转换成HashTable
        array_count = zend_hash_num_elements(arr_hash);//通过zend提供的函数获取一共有多少个元素
        RETURN_LONG(array_count); //返回元素的个数
}
```

#然后修改zend_function_entry maxwelldu_functions[] = { 的内容如下
```
const zend_function_entry maxwelldu_functions[] = {
        PHP_FE(maxwelldu,NULL)
        {NULL,NULL,NULL}
};
```

at the end of the file #Package

#Note that the directory of php-config may be different depending on how PHP is installed

phpize
./configure --with-php-c/bin/php-config
make
make test
make install

#At this time, the extension will be automatically placed in the corresponding extension directory

#Modify the php configuration file, just like adding mysql, memcache and other extensions normally

#Restart apache or php-fpm

extension=maxwelldu.so
service httpd restart
service php-fpm restart

#View what has been installed Extension

php -m

#You can view maxwelldu

# in phpinfo and then you can use it in PHP scripts

<?php
$arr = [
	1, 2, 3, 4, 5
];
echo maxwelldu($arr) == count($arr), PHP_EOL; //打印出1就表示函数返回的数组个数和系统的count函数返回值一样

Reference address:

http://blog.csdn.net/heiyeshuwu/article/details/3453854

http://www.360doc.com/content/13/1226/17/14452132_340319333.shtml

http://www.nowamagic.net/librarys/veda/detail/1467

http://blog.csdn .net/super_ufo/article/details/3863731

http://www.phppan.com/2010/02/php-source-12-return_value/

http://www.ccvita.com/496.html

The above introduces the writing of the first PHP extension to calculate the number of arrays, including the content. I hope it will be helpful to friends who are interested in PHP tutorials.