PHP (Hypertext Preprocessor, originally Personal Home Page ) is a free interpreted language, originally used only for the development of applications present and active on the server side, capable of generating dynamic content on the internet.
The code is interpreted on the server side by PHP module, which also generates the web page to be displayed on the client side.
The language has evolved to provide functionality in the command line, and moreover, gained additional features that allowed additional uses. You can install PHP on most operating systems, for free.
Direct competitor of technology owned by Microsoft ASP, PHP is used in applications such as MediaWiki, Facebook, Drupal, Joomla, WordPress, Magento and Oscommerce.
Created by Rasmus Lerdorf in 1995, PHP has its main production implementation – formal language reference, maintained by an organization called The PHP Group.
The language emerged in mid-1994, as a pack of CGI programs created by Rasmus Lerdorf, named Personal Home Page Tools to replace a set of Perl scripts to be used in developing his personal page.
In 1997, the new package of the language named PHP / FI was released, bringing the Forms Interpreter tool, a SQL command interpreter.
Later, Zeev Suraski developed the PHP parser 3 which featured the first use of object orientation, which gave power to achieve some package, inheritance and had only gave developers the ability to implement properties.
Shortly after, Zeev and Andi Gutmans wrote PHP 4, abandoning altogether the PHP 3, giving more power to the machine language and the most resources of object orientation.
The serious problem that PHP 4 had was creating copies of objects, because the language has not worked with pointers or handlers, as are Java, Ruby and other languages.
The problem had been solved in the current version of PHP, version 5, which already worked with handlers. If you copy an object, you’ll actually copy a pointer, because if there is any change in the original version of the object, all others also experience the modification , which was not the case in PHP 4.5
This is an extremely modularized language, which makes it ideal for installation and use on web servers.
Several modules are created in the repository of extensions PECL (PHP Extension Community Library) and some of these modules are introduced as standard in new versions of the language. It is very similar in data types, syntax and even functions, with C and C++.
It can be embedded in an HTML page depending on the server configuration. There are PHP versions available for the following operating systems: Windows, Linux, FreeBSD, Mac OS, OS/2, AS/400, Novell Netware, RISC OS, AIX, IRIX and Solaris.
Building a dynamic page based on databases with PHP is simple, (in part, recall), this provides support to a large number of databases: Oracle, Sybase, PostgreSQL, InterBase, MySQL, SQLite, MSSQL, Firebird, etc, may disregard the bank with the ADOdb library, among others.
PHP supports the following protocols: IMAP, SNMP, NNTP, POP3, HTTP, LDAP, XML-RPC, SOAP. You can open sockets and interact with other protocols. And the third party libraries further expand these features.
There are initiatives to use PHP as the programming language of fixed systems. The most notable is the PHP – GTK. This is a set of PHP with the GTK library, home of C++, thus making software interoperable between Windows and Linux . In practice, this extension has been little used for projects.