PHP provides a large number of predefined constants to any script
which it runs. Many of these constants, however, are created by
various extensions, and will only be present when those extensions
are available, either via dynamic loading or because they have
been compiled in.
There are five 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:
Table 8-1. A few "magical" PHP constants
| Name | Description |
|---|
| __LINE__ |
The current line number of the file.
|
| __FILE__ |
The full path and filename of the file.
|
| __FUNCTION__ |
The function name. (This was added in PHP 4.3.0.)
|
| __CLASS__ |
The class name. (This was added in PHP 4.3.0.)
|
| __METHOD__ |
The class method name. (This was added in PHP 5.0.0)
|
