PHP Magic Constants
Remarks
Magic constants are distinguished by their __CONSTANTNAME__ form.
There are currently eight magical constants that change depending on where they are used. For example, the value of __LINE__depends on the line that it's used on in your script.
These special constants are case-insensitive and are as follows:
| Name | Description |
|---|---|
__LINE__ | The current line number of the file. |
__FILE__ | The full path and filename of the file with symlinks resolved. If used inside an include, the name of the included file is returned. |
__DIR__ | The directory of the file. If used inside an include, the directory of the included file is returned. This is equivalent to dirname(__FILE__). This directory name does not have a trailing slash unless it is the root directory. |
__FUNCTION__ | The current function name |
__CLASS__ | The class name. The class name includes the namespace it was declared in (e.g. Foo\Bar). When used in a trait method, __CLASS__ is the name of the class the trait is used in. |
__TRAIT__ | The trait name. The trait name includes the namespace it was declared in (e.g. Foo\Bar). |
__METHOD__ | The class method name. |
__NAMESPACE__ | The name of the current namespace. |
Most common use case for these constants is debugging and logging
