New features of PHP4

PHP4.0 is a more effective and reliable dynamic web page development tool. it runs faster than PHP3.0 in most cases, and its script description is stronger and more complex, the most obvious feature is the increase in rate ratio. PHP4.0 these excellent performance is PHP script engine reset PHP 4.0 is more effective, more reliable dynamic web page development tools, in most cases, run faster than PHP 3.0, its script description is more powerful and complex, and the most obvious characteristic is the increase of rate ratio. PHP4.0 these excellent performance is the result of the re-design of the PHP script engine: the engine is fully rewritten from the underlying layer by AndiGutmans and Zeev Suraski. PHP4.0 script engine-Zend Engine-applies a more effective "compilation-fulfillment" paradigm, rather than the "fulfillment-when parsing" model adopted by PHP 3.0.

PHP4 adds or enhances many useful features based on version 3.0. the important features are as follows:

(1) No.

In PHP4, you can assign values to variables using references, which brings great flexibility to programming.

(2) expanded the API module

PHP 4.0 provides an extended PHP interface module for the expanded API module, which is obviously faster than the old API version. Most of the existing and most common interfaces of the PHP module are converted to the extended interface of the application.

(3) active resource release

PHP4 adds the reference counting function. the introduction of this new technique enables PHP4 to take the initiative to manage memory and reduce the burden on developers.

(4) Boolean type

PHP 4.0 supports the Boolean type.

(5) inherent process

In a UNIX environment, PHP 4.0 provides a very intelligent and general natural process. it applies a natural system technique called automake/libtool.

(6) support for COM/DCOM

PHP 4.0 provides support for COM/DCOM (for Windows only) to seamlessly access and visit COM objects.

(7) good compatibility with PHP 3.0

PHP 4.0 is backward compatible with PHP 3.0 code and is close to 100%. Due to the improved system structure of PHP 4, there are some minor differences between the two, but most people will never be able to meet this situation.

(8) configuration

PHP4 redesigned and strengthened PHP. Ini file, which enables PHP. Ini is very easy to configure PHP. This file can be registered by Apache (unix system) or Windows (Windows environment) at runtime ).

(9) encryption support

PHP4 implements complete encryption. these encryption functions are a complete mycrypt library, and PHP 4.0 supports hash functions. Blowfish, TripleDES, MD5, and SHA1 are also applicable encryption algorithms.

(10) type check

PHP 4.0 supports the same identifier used for evaluation type check: '=' (equal sign operator 3) for checking between two values and their types. For example, "3" = 3 will be treated as false (the type is different), and "3" = 3 (equal judgment) will be treated as true.

(11) FTP support

PHP 4.0 supports FTP. Generally, you provide a network interface for downloading a large file through a modem connection. However, if you do need it, you can use PHP.

(12) add function or function enhancement function in PHP4

PHP 4.0 has added many new functions and enhanced the functions of many existing functions. The following are some examples.

Array_count_values ()

Eval ()

Foreach ()

Nclude ()

Ob_end_clean ()

Ob_end_flush ()

Ob_get_contents ()