This document discusses how to build a PHP extension in C. It provides an overview of PHP extensions and the extension development process. It then walks through an example "Hello World" extension, showing how to generate the extension skeleton, add functions in the header and source files, build and install the extension, and test the new functionality. Advanced topics like parameters, return values, memory allocation and preventing memory leaks are also briefly mentioned.

1. Trường đào tạo Lập trình viên Quốc tế
AiTi-Aptech
Build your own PHP Extension
Hanoi PHP Day 2010
Bui Dinh Ngoc
AiTi-Aptech - CAH

2. PHP Extension ?

3. PHP Extension
• You've used extensions ?
• php_mysql , gd , pdo , curl , ...
•

4. PHP Extension
(Zend Engine)
• PHP language written in C
• PHP interpreter written in C too
• And PHP Extension must written in C
• Another PHP implement may be using diffrence language

5. Why and When need
PHP extension ?
1. Buildin PHP function are not enough
2. Existing PHP extension are not enough
3. Pure PHP function are more slow
4. Have C lib can do this for you

6. Prepare
1. Ubuntu Linux
2. GNU C Compiler , build , make utils
3. PHP 5 Dev package : sudo apt-get install php5-dev
4. PHP source code
o sudo svn checkout http://svn.php.net/viewvc/php/php-
src/trunk
o

7. PHP-Src-5.3 tree directory

8. ext_skel.sh script

9. Write Hello World
Extension
//Example function call
<?php
function hello_world() {
return 'Hello World';
}
?>

10. 1. Run ext_skel script : sudo ./ext_skel –extname=hello
2.

11. Result

12. phpize
The phpize command is used to prepare the build environment
for a PHP extension.

14. Edit header file php_hello.h

15. Insert your function
to header file
PHP_FUNCTION(hello); /*My function here*/

16. Edit C source file
- pre declare
const zend_function_entry simhash_functions[] = {
PHP_FE(confirm_hello_compiled, NULL) /* For testing,
remove later. */
PHP_FE(hello, NULL)
{NULL, NULL, NULL} /* Must be the last line in
hello_functions[] */
};

17. Implement function
PHP_FUNCTION(hello)
{
php_printf(“Hello, world!n”);
}

18. Build - Run some script
1. sudo ./configure
2. sudo make
3. ls modules -> hello.so

19. Test
1. Deploy file hello.so
2. Check new extension is loaded by phpinfo function
3. You also can test using existed hello.php script in ext dir

20. Advance !
1. Build php function with parameter
2. Return value
3. Memory allocation
4. Anti Memory leak
5. Array
6. String
7. Global variable
8. PHP.INI variable
9. ........

21. Function with parameter
function hello_add($a, $b) {
$sum = (int)$a + (float)$b;
return $sum;
}

22. Function with parameter
PHP_FUNCTION(hello_add)
{
long a;
double b;
if (zend_parse_parameters(ZEND_NUM_ARGS()
TSRMLS_CC, "ld", &a, &b) == FAILURE) {
RETURN_NULL();
}
RETURN_DOUBLE(a + b);
}

23. Return value
1. bool
2. int
3. double Only 6 return type
4. resource
5. array
6. object

24. Return value (macro)
RETURN_LONG() for integer values
RETURN_DOUBLE() for floating point values
RETURN_BOOL() for true/false values
RETURN_NULL() for null value
.....

25. Memory allocation

26. Anti Memory leak
• In C, memory management always very hard .
• Wrapper functions provides you with a safety net and some
helpful debugging facilities
• But convert existing C source can't use wrapper functions

27. Reference
1. http://i-php.net/2010/10/t-build-extension-cho-php/
2. http://devzone.zend.com/article/1021
3. "Programming PHP" by Rasmus Lerdorf and Kevin