Interpretation of the underlying development principles of PHP7: Master the key elements of PHP extension development

Interpretation of the underlying development principles of PHP7: Master the key elements of PHP extension development

Introduction:
PHP is a scripting language that is widely used in Web development. Its ease of use and flexibility make it the first choice of many developers. As a new version of PHP, PHP7 has not only greatly improved performance and security, but also introduced many new features. Understanding the underlying development principles of PHP7, especially mastering the key elements of PHP extension development, will be very valuable to PHP developers.

1. The importance of understanding the underlying development principles of PHP
PHP is an interpreted scripting language, which needs to rely on the interpreter for parsing and execution during runtime. Understanding the underlying development principles of PHP means being able to have an in-depth understanding of PHP's internal mechanisms and operating principles, so that you can better utilize and optimize the underlying features during development. For extension developers, it is also very necessary to understand the underlying development principles of PHP, because extension development involves interacting with the PHP interpreter. Understanding the underlying principles helps to better write efficient and reliable extensions.

2. Master the key elements of PHP extension development

1. Extension structure
   In PHP7, extensions exist in the form of dynamic link libraries, which require a customized C The module code of the language and links the extension with the PHP interpreter dependency at compile time. A typical PHP extension structure includes module entry, function entry and constants. As the module entry point, the module entry defines the basic information of the extension, and the function entry defines the functions that can be called by PHP.

The following is a simple example showing the basic structure of a PHP extension:

#include <php.h>

PHP_FUNCTION(hello_world) {
    php_printf("Hello, World!
");
}

zend_function_entry hello_functions[] = {
    PHP_FE(hello_world, NULL)
    {NULL, NULL, NULL}
};

zend_module_entry hello_module_entry = {
    STANDARD_MODULE_HEADER,
    "hello",
    hello_functions,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    PHP_SAY_HELLO_VERSION,
    STANDARD_MODULE_PROPERTIES
};

ZEND_GET_MODULE(hello)

2. Memory Management
   PHP uses the Zend memory management system at the bottom. Is a mechanism for managing memory. In PHP extension development, we need to allocate and release memory through the memory management functions provided by Zend to avoid memory leaks or memory access errors. Commonly used memory management functions include emalloc(), ecalloc(), erealloc(), efree(), etc.

The following is an example of using Zend memory management:

PHP_FUNCTION(hello_world) {
    char *msg = emalloc(20);
    memcpy(msg, "Hello, World!", 14);
    msg[14] = '';
    
    php_printf(msg);
    efree(msg);
}

3. Data type conversion
   In PHP extension development, it is often necessary to interact with PHP data types . Zend provides some functions internally to facilitate data type conversion. Among them, the zval structure represents the data type of PHP, and zval can be directly assigned and operated through the ZVAL_* macro.

The following is an example of using zval for data type conversion:

PHP_FUNCTION(hello_world) {
    zval str;
    ZVAL_STRING(&str, "Hello, World!");

    php_printf(Z_STRVAL(str));
    zval_dtor(&str);
}

Conclusion:
Through the interpretation of the underlying development principles of PHP, we understand the key elements of PHP extension development . Mastering the basic knowledge of PHP extension development will be very valuable for developers who want to deeply understand the internal mechanisms of PHP and further explore and unleash the potential of PHP. Through actual code examples, we can better understand and apply these principles, improve the ability and technical level of PHP extension development, and lay the foundation for better development of high-performance and reliable PHP applications.

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