unset(1f) [opensolaris man page]

set(1F) 							   FMLI Commands							   set(1F)

NAME

       set, unset - set and unset local or global environment variables

SYNOPSIS

       set [-l variable [=value]] ...

       set [-e variable [=value]] ...

       set [-ffile variable [=value]]... ...

       unset -l variable...

       unset -f file variable...

DESCRIPTION

       The set command sets variable in the environment, or adds variable=value to file. If variable is not equated it to a value, set expects the
       value to be on stdin. The unset command removes variable. Note that the FMLI predefined, read-only variables (such as ARG1), may not be set
       or unset.

       Note  that  at  least one of the above options must be used for each variable being set or unset. If you set a variable with the -ffilename
       option, you must thereafter include filename in references to that variable. For example, ${(file)VARIABLE}.

       FMLI inherits the UNIX environment when invoked.

OPTIONS

       -l	 Sets or unsets the specified variable in the local environment. Variables set with -l will not be inherited by processes  invoked
		 from FMLI.

       -e	 Sets  the specified variable in the UNIX environment. Variables set with -e will be inherited by any processes started from FMLI.
		 Note that these variables cannot be unset.

       -ffile	 Sets or unsets the specified variable in the global environment. The argument file is the name, or pathname, of a file containing
		 lines of the form variable=value. file will be created if it does not already exist. Note that no space intervenes between -f and
		 file.

EXAMPLES

       Example 1 A sample output of set command.

       Storing a selection made in a menu:

	 name=Selection 2
	 action=`set -l SELECTION=2`close

NOTES

       Variables set to be available to the UNIX environment (those set using the -e option) can only be set for the current fmli process and  the
       processes it calls.

       When  using the -f option, unless file is unique to the process, other users of FMLI on the same machine will be able to expand these vari-
       ables, depending on the read/write permissions on file.

       A variable set in one frame may be referenced or unset in any other frame. This includes local variables.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       env(1), sh(1), attributes(5)

SunOS 5.11							    5 Jul 1990								   set(1F)

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)