PHP 尽管提供了大量有用的函数，但是在特殊情况下还可能需要进行扩展编程，比如大量的 PECL（PHP Extension Community Library）就是以扩展的形式提供的(动态链接库dll文件)，它们比 PEAR 的运行效率要高很多。
PHP 扩展是用 C 或 C++ 编写的，需要编译成动态连接库 dll 文件后在 PHP 环境下注册后才能使用。
编写 PHP 扩展的软件要求：
VC++6.0 或 VC++.NET 环境。
PHP 的源代码，需要编译。
如果不愿意编译 PHP 的源代码，可以再下载 PHP 的已经编译成功的二进制代码(就是我们部署 PHP 运行环境的那些文件包)。注意分别下载的源文件包和已编译包，它们的版本必须一致。
过程：
1，安装 VC++6.0，并选择把其可执行文件路径加入环境变量中，使在命令行环境任意路径下可以运行编译器。
2，安装 PHP 运行环境，并与 IIS 正确集成在一起。假设使用的 PHP 版本为 5.2.5，下载 php-5.2.5-Win32.zip 二进制包和 php-5.2.5.tar.gz 源代码包。安装环境为 C:\php-5.2.5-Win32。分别把源代码包和二进制包解压到该文件夹下。从 php.ini-recommended 拷贝生成一个 php.ini 文件。
3，建立 C:\php-5.2.5-Win32\Release_TS 文件夹，拷贝 C:\php-5.2.5-Win32\dev\php5ts.lib 文件到这里。
4，进入 C:\php-5.2.5-Win32\ext 文件夹，运行命令：
C:\php-5.2.5-Win32\ext>..\php.exe ext_skel_win32.php --extname=myphpext
Creating directory myphpext
Creating basic files: config.m4 config.w32 .cvsignore myphpext.c php_myphpext.h
CREDITS EXPERIMENTAL tests/001.phpt myphpext.php [done].
To use your new extension, you will have to execute the following steps:
1. $ cd ..
2. $ vi ext/myphpext/config.m4
3. $ ./buildconf
4. $ ./configure --[with|enable]-myphpext
5. $ make
6. $ ./php -f ext/myphpext/myphpext.php
7. $ vi ext/myphpext/myphpext.c
8. $ make
Repeat steps 3-6 until you are satisfied with ext/myphpext/config.m4 and
step 6 confirms that your module is compiled into PHP. Then, start writing
code and repeat the last two steps as often as necessary.
结果在 ext 下生成一个文件夹 myphpext，包含一个 PHP 扩展应用编程框架。myphpext 可以任意取名，将来生成的 dll 文件格式为 php_[extname].dll，我们生成的就是 php_myphpext.dll。运行结果的提示信息 1.2...8 主要是对 Linux/Unix 环境而言的，我们不必理会。其实 config.m4 文件在 Windows 下也可能需要修改，但是对于我们简单的框架暂时还用不着。
文件夹 myphpext 包含若干个文件，其中：
myphpext.dsp 是工程文件，后边还要用；
myphpext.php 扩展测试文件；
php_myphpext.h 扩展函数定义头文件
myphpext.c 扩展函数具体实现
以上 2 个重要的文件内容：
php_myphpext.h 文件：
/*
+----------------------------------------------------------------------+
| PHP Version 5 |
+----------------------------------------------------------------------+
| Copyright (c) 1997-2007 The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.01 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| http://www.php.net/license/3_01.txt |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@php.net so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Author: |
+----------------------------------------------------------------------+
*/ /* $Id: header,v 1.16.2.1.2.1 2007/01/01 19:32:09 iliaa Exp $ */ #ifndef PHP_MYPHPEXT_H
#define PHP_MYPHPEXT_H extern zend_module_entry myphpext_module_entry;
#define phpext_myphpext_ptr &myphpext_module_entry #ifdef PHP_WIN32
#define PHP_MYPHPEXT_API __declspec(dllexport)
#else
#define PHP_MYPHPEXT_API
#endif #ifdef ZTS
#include "TSRM.h"
#endif PHP_MINIT_FUNCTION(myphpext);
PHP_MSHUTDOWN_FUNCTION(myphpext);
PHP_RINIT_FUNCTION(myphpext);
PHP_RSHUTDOWN_FUNCTION(myphpext);
PHP_MINFO_FUNCTION(myphpext); PHP_FUNCTION(confirm_myphpext_compiled); /* For testing, remove later. */
PHP_FUNCTION(HelloPHP); /*
Declare any global variables you may need between the BEGIN
and END macros here: ZEND_BEGIN_MODULE_GLOBALS(myphpext)
long global_value;
char *global_string;
ZEND_END_MODULE_GLOBALS(myphpext)
*/ /* In every utility function you add that needs to use variables
in php_myphpext_globals, call TSRMLS_FETCH(); after declaring other
variables used by that function, or better yet, pass in TSRMLS_CC
after the last function argument and declare your utility function
with TSRMLS_DC after the last declared argument. Always refer to
the globals in your function as MYPHPEXT_G(variable). You are
encouraged to rename these macros something shorter, see
examples in any other php module directory.
*/ #ifdef ZTS
#define MYPHPEXT_G(v) TSRMG(myphpext_globals_id, zend_myphpext_globals *, v)
#else
#define MYPHPEXT_G(v) (myphpext_globals.v)
#endif #endif /* PHP_MYPHPEXT_H */ /*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: noet sw=4 ts=4 fdm=marker
* vim<600: noet sw=4 ts=4
*/
myphpext.c 文件：
/*
+----------------------------------------------------------------------+
| PHP Version 5 |
+----------------------------------------------------------------------+
| Copyright (c) 1997-2007 The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.01 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| http://www.php.net/license/3_01.txt |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@php.net so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Author: |
+----------------------------------------------------------------------+
*/ /* $Id: header,v 1.16.2.1.2.1 2007/01/01 19:32:09 iliaa Exp $ */ #ifdef HAVE_CONFIG_H
#include "config.h"
#endif #include "php.h"
#include "php_ini.h"
#include "ext/standard/info.h"
#include "php_myphpext.h" /* If you declare any globals in php_myphpext.h uncomment this:
ZEND_DECLARE_MODULE_GLOBALS(myphpext)
*/ /* True global resources - no need for thread safety here */
static int le_myphpext; /* {{{ myphpext_functions[]
*
* Every user visible function must have an entry in myphpext_functions[].
*/
zend_function_entry myphpext_functions[] = {
PHP_FE(confirm_myphpext_compiled, NULL) /* For testing, remove later. */
PHP_FE(HelloPHP, NULL)
{NULL, NULL, NULL} /* Must be the last line in myphpext_functions[] */
};
/* }}} */ /* {{{ myphpext_module_entry
*/
zend_module_entry myphpext_module_entry = {
#if ZEND_MODULE_API_NO >= 20010901
STANDARD_MODULE_HEADER,
#endif
"myphpext",
myphpext_functions,
PHP_MINIT(myphpext),
PHP_MSHUTDOWN(myphpext),
PHP_RINIT(myphpext), /* Replace with NULL if there's nothing to do at request start */
PHP_RSHUTDOWN(myphpext), /* Replace with NULL if there's nothing to do at request end */
PHP_MINFO(myphpext),
#if ZEND_MODULE_API_NO >= 20010901
"0.1", /* Replace with version number for your extension */
#endif
STANDARD_MODULE_PROPERTIES
};
/* }}} */ #ifdef COMPILE_DL_MYPHPEXT
ZEND_GET_MODULE(myphpext)
#endif /* {{{ PHP_INI
*/
/* Remove comments and fill if you need to have entries in php.ini
PHP_INI_BEGIN()
STD_PHP_INI_ENTRY("myphpext.global_value", "42", PHP_INI_ALL, OnUpdateLong, global_value, zend_myphpext_globals, myphpext_globals)
STD_PHP_INI_ENTRY("myphpext.global_string", "foobar", PHP_INI_ALL, OnUpdateString, global_string, zend_myphpext_globals, myphpext_globals)
PHP_INI_END()
*/
/* }}} */ /* {{{ php_myphpext_init_globals
*/
/* Uncomment this function if you have INI entries
static void php_myphpext_init_globals(zend_myphpext_globals *myphpext_globals)
{
myphpext_globals->global_value = 0;
myphpext_globals->global_string = NULL;
}
*/
/* }}} */ /* {{{ PHP_MINIT_FUNCTION
*/
PHP_MINIT_FUNCTION(myphpext)
{
/* If you have INI entries, uncomment these lines
REGISTER_INI_ENTRIES();
*/
return SUCCESS;
}
/* }}} */ /* {{{ PHP_MSHUTDOWN_FUNCTION
*/
PHP_MSHUTDOWN_FUNCTION(myphpext)
{
/* uncomment this line if you have INI entries
UNREGISTER_INI_ENTRIES();
*/
return SUCCESS;
}
/* }}} */ /* Remove if there's nothing to do at request start */
/* {{{ PHP_RINIT_FUNCTION
*/
PHP_RINIT_FUNCTION(myphpext)
{
return SUCCESS;
}
/* }}} */ /* Remove if there's nothing to do at request end */
/* {{{ PHP_RSHUTDOWN_FUNCTION
*/
PHP_RSHUTDOWN_FUNCTION(myphpext)
{
return SUCCESS;
}
/* }}} */ /* {{{ PHP_MINFO_FUNCTION
*/
PHP_MINFO_FUNCTION(myphpext)
{
php_info_print_table_start();
php_info_print_table_header(2, "myphpext support", "enabled");
php_info_print_table_end(); /* Remove comments if you have entries in php.ini
DISPLAY_INI_ENTRIES();
*/
}
/* }}} */ /* Remove the following function when you have succesfully modified config.m4
so that your module can be compiled into PHP, it exists only for testing
purposes. */ /* Every user-visible function in PHP should document itself in the source */
/* {{{ proto string confirm_myphpext_compiled(string arg)
Return a string to confirm that the module is compiled in */
PHP_FUNCTION(confirm_myphpext_compiled)
{
char *arg = NULL;
int arg_len, len;
char *strg; if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &arg, &arg_len) == FAILURE) {
return;
} len = spprintf(&strg, 0, "Congratulations! You have successfully modified ext/%.78s/config.m4. Module %.78s is now compiled into PHP.", "myphpext", arg);
RETURN_STRINGL(strg, len, 0);
} PHP_FUNCTION(HelloPHP)
{
php_printf("Hello, PHP v5.2.5 - 2008-3-28");
} /* }}} */
/* The previous line is meant for vim and emacs, so it can correctly fold and
unfold functions in source code. See the corresponding marks just before
function definition, where the functions purpose is also documented. Please
follow this convention for the convenience of others editing your code.
*/ /*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: noet sw=4 ts=4 fdm=marker
* vim<600: noet sw=4 ts=4
*/
注意本例定义了一个函数 HelloPHP。在 php_myphpext.h 文件中定义：
PHP_FUNCTION(HelloPHP);
在 myphpext.c 中有 2 处地方：
PHP_FE(HelloPHP, NULL) 语句把我们自己的函数加入入口数组中。
以下定义了 HelloPHP 函数的内容:
PHP_FUNCTION(HelloPHP)
{
php_printf("Hello, PHP v5.2.5 - 2008-3-28");
}
其实还有个 confirm_myphpext_compiled 函数，是自动产生的，用于测试，与我们的自定义函数用法一模一样。
5，编译、链接，生成最终的文件。
C:\php-5.2.5-Win32\ext>msdev myphpext\myphpext.dsp /MAKE "myphpext - Win32 Release_TS"
-----------Configuration: myphpext - Win32 Release_TS-----------
Compiling...
myphpext.c
Linking...
Creating library Release_TS/php_myphpext.lib and object Release_TS/php_myphpext.exp
php_myphpext.dll - 0 error(s), 0 warning(s)
最终在 C:\php-5.2.5-Win32\Release_TS 下生成了扩展库 php_myphpext.dll。
6，部署：
把 php_myphpext.dll 拷贝到 C:\php-5.2.5-Win32\ext 文件夹下。修改 php.ini 文件：
加语句 extension=php_myphpext.dll。
再注意 extension 路径的指向，需要把 ;extension_dir = "./" 语句的注释去掉，再修改为 extension_dir = "C:\php-5.2.5-Win32\ext"。
最后一定要重启 IIS 服务器。
7，测试：
把 myphpext.php 拷贝到 Web 服务器根下（myphpext.php 的代码也值得一看），在本机用浏览器打开：http://localhost/myphpext.php，应该能看到以下信息：
Functions available in the test extension:
confirm_myphpext_compiled
HelloPHP
Congratulations! You have successfully modified ext/myphpext/config.m4. Module myphpext is now compiled into PHP.
再建立一个 test.php 文件，内容为：
<?php
HelloPHP();
?>