PHP has large number of predefined constants. This HOWTO will present the seven most important, most practical and most useful PHP Magic Constants. __FILE__ – The full path and filename of the file. __DIR__ – The directory of the file. __FUNCTION__ – The function name. __CLASS__ – The class name. __METHOD__ – The class method name. __LINE__ – The current line number of the file. __NAMESPACE__ – The name of the current namespace This is example PHP script with comments, which demonstrate howto use all previously mentioned PHP Magic Constants.