Instructions for using PHP define functions _php Tips

Pre-defined constants in PHP:

__file__

The script file name that is currently being processed. If used in a contained file, its value is the included file, not the file name that contains it.

__line__

The current number of rows for the file being processed.

Php_version

Represents the current version of the PHP processor, such as: ' 3.0.8-dev '.

Php_os

The operating system name of the PHP processor, such as: ' Linux '.

TRUE

Truth

FALSE

False value

You can define more constants with the Define function.

For example, define constants:

Define ("CONSTANT", "Hello world.");
Echo CONSTANT; Outputs "Hello world."
?>
With examples of __file__ and __line__

function Report_error ($file, $line, $message) {
echo "An error occured in $file" line $line: $message. ";
}
Report_error (__file__,__line__, "something went wrong!");
?>