php man page for is_null

IS_NULL(3)								 1								IS_NULL(3)

is_null - Finds whether a variable is NULL

SYNOPSIS
       bool is_null (mixed  $var)

DESCRIPTION
	Finds whether the given variable is NULL.

PARAMETERS
	      o $var
		- The variable being evaluated.

RETURN VALUES
	Returns TRUE if $var is null, FALSE otherwise.

EXAMPLES
       Example #1

	      is_null(3) example

	      <?php

	      error_reporting(E_ALL);

	      $foo = NULL;
	      var_dump(is_null($inexistent), is_null($foo));

	      ?>

	      Notice: Undefined variable: inexistent in ...
	      bool(true)
	      bool(true)

SEE ALSO
       The NULL type, isset(3), is_bool(3), is_numeric(3), is_float(3), is_int(3), is_string(3), is_object(3), is_array(3).

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