ini_set()

string ini_set ( string $varname, string $newvalue )
Sets the value of the given configuration option. The configuration option will keep this new value during the script's execution, and will be restored at the script's ending.

PHP Objects

Basic Object-oriented programming functionality was added in PHP 3. Handling of objects was completely rewritten for PHP 5, allowing for better performance and more features. In previous versions of PHP, objects were handled like primitive types. The drawback of this method was that the whole object was copied when a variable was assigned, or passed as a parameter to a method. In the new approach, objects are referenced by handle, and not by value. PHP 5 introduced private and protected member variables and methods, along with abstract classes and abstract methods. It also introduced a standard way of declaring constructors and destructors similar to that of other object-oriented languages, such as C++, and an exception handling model similar to that of other programming languages.
The static method and class variable features in Zend Engine 2 do not work the way some expect. There is no virtual table feature in the engine, so the static variables are bound with a name at compile time instead of with a reference.
class foo extends bar
{
function __construct()
{
}
public static function thisstaticfunc()
{
}
}
The above very basic example shows how to define a class, foo, that inherits from class bar. Additionally, the function, mystaticfunc, is a public static function that is called with foo::thisstaticfunc();.
If the developer asks to create a copy of an object by using the reserved word clone, the Zend engine will check if a __clone() method has been defined or not. If not, it will call a default __clone() which will copy all of the object's properties. If a __clone() method is defined, then it will be responsible for setting the necessary properties in the created object. For convenience, the engine will supply a function that imports all of the properties from the source object, so that they can start with a by-value replica of the source object, and only override properties that need to be changed

PHP Data types

PHP stores whole numbers in a platform-dependent range. This range is typically that of 32-bit signed integers. Integer variables can be assigned using decimal (positive and negative), octal and hexadecimal notations. Real numbers are also stored in a platform-specific range. They can be specified using floating point notation, or two forms of scientific notation.
PHP has a native Boolean type, named "boolean", similar to the native Boolean types in Java and C++. Using the Boolean type conversion rules, non-zero values can be interpreted as true and zero as false, as in Perl.
The null data type represents a variable that has no value. The only value in the null data type is NULL.
Variables of the "resource" type represent references to resources from external sources. These are typically created by functions from a particular extension, and can only be processed by functions from the same extension. Examples include file, image and database resources.
Arrays support both numeric and string indices, and are heterogeneous. Arrays can contain elements of any type that PHP can handle, including resources, objects, and even other arrays. Order is preserved in lists of values and in hashes with both keys and values, and the two can be intermingled

PHP Command-line scripting

PHP also provides a command line interface SAPI for developing shell and desktop applications, daemons, log parsing, or other system administration tasks. PHP is increasingly used on the command line for tasks that have traditionally been the domain of Perl, Python, awk, or shell scripting

PHP Server-side scripting

Originally designed to create dynamic web pages, PHP's principal focus is server-side scripting. While running the PHP parser with a web server and web browser, the PHP model can be compared to other server-side scripting languages such as Microsoft's ASP.NET system, Sun Microsystems' JavaServer Pages, mod_perl and the Ruby on Rails framework, as they all provide dynamic content to the client from a web server. To more directly compete with the "framework" approach taken by these systems, Zend is working on the Zend Framework - an emerging (as of June 2006) set of PHP building blocks and best practices; other PHP frameworks along the same lines include CakePHP, PRADO and Symfony.
The LAMP architecture has become popular in the Web industry as a way of deploying inexpensive, reliable, scalable, secure web applications. PHP is commonly used as the P in this bundle alongside Linux, Apache and MySQL, although the P can also refer to Python or Perl. PHP can be used with a large number of relational database management systems, runs on all of the most popular web servers and is available for many different operating systems. This flexibility means that PHP has a wide installation base across the Internet; over 19 million Internet domains are currently hosted on servers with PHP installed

PHP Usage

PHP generally runs on a web server, taking PHP code as its input and creating Web pages as output. However, it can also be used for command-line scripting and client-side GUI applications. PHP can be deployed on most web servers and on almost every operating system and platform free of charge. The PHP Group also provides the complete source code for users to build, customize and extend for their own use.
PHP primarily acts as a filter. The PHP program takes input from a file or stream containing text and special PHP instructions and outputs another stream of data for display.
From PHP 4, the PHP parser compiles input to produce bytecode for processing by the Zend Engine, giving improved performance over its interpreter predecessor. PHP 5 uses the Zend Engine II.

PHP History

PHP was written as a set of CGI binaries in the C programming language by the Danish/Greenlandic programmer Rasmus Lerdorf in 1994, to replace a small set of Perl scripts he had been using to maintain his personal homepage.[4] Lerdorf initially created PHP to display his résumé and to collect certain data, such as how much traffic his page was receiving. Personal Home Page Tools was publicly released on 8 June 1995 after Lerdorf combined it with his own Form Interpreter to create PHP/FI (this release is considered PHP version 2).[5]
Zeev Suraski and Andi Gutmans, two Israeli developers at the Technion IIT, rewrote the parser in 1997 and formed the base of PHP 3, changing the language's name to the recursive initialism PHP: Hypertext Preprocessor. The development team officially released PHP/FI 2 in November 1997 after months of beta testing. Public testing of PHP 3 began and the official launch came in June 1998. Suraski and Gutmans then started a new rewrite of PHP's core, producing the Zend Engine in 1999.[6] They also founded Zend Technologies in Ramat Gan, Israel, which actively manages the development of PHP.
In May 2000, PHP 4, powered by the Zend Engine 1.0, was released. The most recent update released by The PHP Group, is for the older PHP version 4 code branch which, as of May 2007, is up to version 4.4.7. PHP 4 will be supported by security updates until 8 August 2008[7].
On July 13, 2004, PHP 5 was released powered by the new Zend Engine II. PHP 5 included new features such as:[8]
Improved support for object-oriented programming
The PHP Data Objects extension, which defines a lightweight and consistent interface for accessing databases
Performance enhancements
Better support for MySQL
Embedded support for SQLite
Integrated SOAP support
Data iterators
Error handling via exceptions