empty() returns FALSE if var has a non-empty and non-zero value. In otherwords, "", 0, "0", NULL, FALSE, array(), var $var;, and objects with empty properties, are all considered empty. TRUE is returned if var is empty.
empty() is the opposite of (boolean) var, except that no warning is generated when the variable is not set. See converting to boolean for more information.
Example 1. A simple empty() / isset() comparison.
Note: Because this is a language construct and not a function, it cannot be called using variable functions
Note: empty() only checks variables as anything else will result in a parse error. In otherwords, the following will not work: empty(addslashes($name)).