PHP Magic Constants
PHP Magic Constants
PHP has nine predefined constants that change value depending on where they are used, also called the "magic constants".
The magic constants provide information about the current state of the script, such as the file name, directory name, line number, function name, class name, and more.
The magic constants always start and end with double underscores (__), except for the ClassName::class constant.
The magic constants are not case-sensitive, meaning __LINE__ returns the same as __line__.
The following table lists the magic constants, with descriptions and examples:
| Constant | Description | |
|---|---|---|
| __CLASS__ | If used inside a class, the class name is returned. | Try it » |
| __DIR__ | The directory of the file. | Try it » |
| __FILE__ | The file name including the full path. | Try it » |
| __FUNCTION__ | If inside a function, the function name is returned. | Try it » |
| __LINE__ | The current line number of the file. | Try it » |
| __METHOD__ | If used inside a function that belongs to a class, both class and function name is returned. | Try it » |
| __NAMESPACE__ | If used inside a namespace, the name of the namespace is returned. | Try it » |
| __TRAIT__ | If used inside a trait, the trait name is returned. | Try it » |
| ClassName::class | Returns the name of the specified class and the name of the namespace, if any. | Try it » |
