UNSET(3)								 1								  UNSET(3)

unset - Unset a given variable

SYNOPSIS

       void unset (mixed  $var, [mixed	$...])

DESCRIPTION

       unset(3) destroys the specified variables.

	The behavior of unset(3) inside of a function can vary depending on what type of variable you are attempting to destroy.

	If  a  globalized variable is unset(3) inside of a function, only the local variable is destroyed. The variable in the calling environment
       will retain the same value as before unset(3) was called.

       <?php
       function destroy_foo()
       {
	   global $foo;
	   unset($foo);
       }

       $foo = 'bar';
       destroy_foo();
       echo $foo;
       ?>

       The above example will output:

       bar

	To unset(3) a global variable inside of a function, then use the $GLOBALS array to do so:

       <?php
       function foo()
       {
	   unset($GLOBALS['bar']);
       }

       $bar = "something";
       foo();
       ?>

	If a variable that is PASSED BY REFERENCE is unset(3) inside of a function, only the local variable is	destroyed.  The  variable  in  the
       calling environment will retain the same value as before unset(3) was called.

       <?php
       function foo(&$bar)
       {
	   unset($bar);
	   $bar = "blah";
       }

       $bar = 'something';
       echo "$bar
";

       foo($bar);
       echo "$bar
";
       ?>

       The above example will output:

       something
       something

	If  a static variable is unset(3) inside of a function, unset(3) destroys the variable only in the context of the rest of a function. Fol-
       lowing calls will restore the previous value of a variable.

       <?php
       function foo()
       {
	   static $bar;
	   $bar++;
	   echo "Before unset: $bar, ";
	   unset($bar);
	   $bar = 23;
	   echo "after unset: $bar
";
       }

       foo();
       foo();
       foo();
       ?>

       The above example will output:

       Before unset: 1, after unset: 23
       Before unset: 2, after unset: 23
       Before unset: 3, after unset: 23

PARAMETERS

	      o $var
		- The variable to be unset.

	      o $...
		- Another variable ...

RETURN VALUES

	No value is returned.

EXAMPLES

       Example #1

	      unset(3) example

	      <?php
	      // destroy a single variable
	      unset($foo);

	      // destroy a single element of an array
	      unset($bar['quux']);

	      // destroy more than one variable
	      unset($foo1, $foo2, $foo3);
	      ?>

       Example #2

	      Using (unset) casting

	      (unset) casting is often confused with the unset(3) function.  (unset) casting serves only as a NULL-type cast, for completeness. It
	      does not alter the variable it's casting.

	      <?php
	      $name = 'Felipe';

	      var_dump((unset) $name);
	      var_dump($name);
	      ?>

	      The above example will output:

	      NULL
	      string(6) "Felipe"

NOTES

       Note

	      Because this is a language construct and not a function, it cannot be called using variable functions.

       Note

	       It is possible to unset even object properties visible in current context.

       Note

	       It is not possible to unset $this inside an object method since PHP 5.

       Note

	       When using unset(3) on inaccessible object properties, the __unset() overloading method will be called, if declared.

SEE ALSO

       isset(3), empty(3), __unset(), array_splice(3).

PHP Documentation Group 														  UNSET(3)