<?xml version="1.0" encoding="utf-8"?>
 <reference id="ref.variables">
  <title>Variable Functions</title>
  <titleabbrev>Variables</titleabbrev>

  <refentry id="function.doubleval">
   <refnamediv>
    <refname>doubleval</refname>
    <refpurpose>Get double value of a variable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>double</type><methodname>doubleval</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     Returns the double (floating point) value of
     <parameter>var</parameter>.
    </simpara>
    <para>
     <parameter>Var</parameter> may be any scalar type. You cannot use
     <function>doubleval</function> on arrays or objects.
    <informalexample>
      <programlisting role="php">
$var = '122.34343The';
$double_value_of_var = doubleval ($var);
print $double_value_of_var; // prints 122.34343
      </programlisting>
     </informalexample>
    </para>
    <simpara>
     See also <function>intval</function>,
     <function>strval</function>, <function>settype</function> and
     <link linkend="language.types.type-juggling">Type
     juggling</link>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.empty">
   <refnamediv>
    <refname>empty</refname>
    <refpurpose>Determine whether a variable is set</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>int</type><methodname>empty</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <para>
     Returns &false; if <parameter>var</parameter> is set and has a
     non-empty or non-zero value; &true; otherwise.
     <informalexample>
      <programlisting role="php">
$var = 0;

if (empty($var)) {  // evaluates true
    echo '$var is either 0 or not set at all';
}

if (!isset($var)) { // evaluates false
    echo '$var is not set at all';
}
      </programlisting>
     </informalexample>
    </para>
    <simpara>
     Note that this is meaningless when used on anything which isn't a
     variable; i.e. <command>empty (addslashes ($name))</command> has
     no meaning since it would be checking whether something which
     isn't a variable is a variable with a &false; value.
    </simpara>
    <simpara>
     See also <function>isset</function> and
     <function>unset</function>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.gettype">
   <refnamediv>
    <refname>gettype</refname>
    <refpurpose>Get the type of a variable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>string</type><methodname>gettype</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <para>
     Returns the type of the PHP variable
     <parameter>var</parameter>.
    </para>
    <para>
     Possibles values for the returned string are:
     <itemizedlist>
      <listitem>
       <simpara>"boolean"</simpara>
      </listitem>
      <listitem>
       <simpara>"integer"</simpara>
      </listitem>
      <listitem>
       <simpara>"double"</simpara>
      </listitem>
      <listitem>
       <simpara>"string"</simpara>
      </listitem>
      <listitem>
       <simpara>"array"</simpara>
      </listitem>
      <listitem>
       <simpara>"object"</simpara>
      </listitem>
      <listitem>
       <simpara>"resource"</simpara>
      </listitem>
      <listitem>
       <simpara>"user function" (PHP 3 only, deprecated)</simpara>
      </listitem>
      <listitem>
       <simpara>"unknown type"</simpara>
      </listitem>
     </itemizedlist>
    </para>
    <para>
     For PHP 4, you should use <function>function_exists</function> and
     <function>method_exists</function> to replace the prior usage of
     <function>gettype</function> on a function.
    </para>
    <para>
     See also <function>settype</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.intval">
   <refnamediv>
    <refname>intval</refname>
    <refpurpose>Get integer value of a variable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>int</type><methodname>intval</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
      <methodparam choice="opt"><type>int</type><parameter>base</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     Returns the integer value of <parameter>var</parameter>,
     using the specified base for the conversion (the default is
     base 10).
    </simpara>
    <simpara>
     <parameter>Var</parameter> may be any scalar type. You cannot use
     <function>intval</function> on arrays or objects.
    </simpara>
    <simpara>
     See also <function>doubleval</function>,
     <function>strval</function>, <function>settype</function> and
     <link linkend="language.types.type-juggling">Type
     juggling</link>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.is-array">
   <refnamediv>
    <refname>is_array</refname>
    <refpurpose>Finds whether a variable is an array</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_array</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <para>
     Returns &true; if <parameter>var</parameter> is an array, &false;
     otherwise.
    </para>
    <para>
     See also <function>is_double</function>,
     <function>is_float</function>,
     <function>is_int</function>,
     <function>is_integer</function>,
     <function>is_real</function>,
     <function>is_string</function>,
     <function>is_long</function>, and
     <function>is_object</function>.
    </para>
   </refsect1>
  </refentry>
  
  <refentry id="function.is-bool">
   <refnamediv>
    <refname>is_bool</refname>
     <refpurpose>
      Finds out whether a variable is a boolean
     </refpurpose>
    </refnamediv>
    <refsect1>
     <title>Description</title>
     <methodsynopsis>
       <type>bool</type><methodname>is_bool</methodname>
       <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
     <para>
      Returns &true; if the <parameter>var</parameter> parameter is 
      a boolean.
     </para>
     <para>
     See also <function>is_array</function>,
     <function>is_double</function>,
     <function>is_float</function>,
     <function>is_int</function>,
     <function>is_integer</function>,
     <function>is_real</function>,
     <function>is_string</function>,
     <function>is_long</function>, and
     <function>is_object</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-double">
   <refnamediv>
    <refname>is_double</refname>
    <refpurpose>Finds whether a variable is a double</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_double</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <para>
     Returns &true; if <parameter>var</parameter> is a double,
     &false; otherwise.
    </para>
    <para>
     See also <function>is_array</function>,
     <function>is_bool</function>,
     <function>is_float</function>,
     <function>is_int</function>,
     <function>is_integer</function>,
     <function>is_real</function>,
     <function>is_string</function>,
     <function>is_long</function>, and
     <function>is_object</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-float">
   <refnamediv>
    <refname>is_float</refname>
    <refpurpose>Finds whether a variable is a float</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_float</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     This function is an alias for <function>is_double</function>.
    </simpara>
    <simpara>
     See also <function>is_double</function>,
     <function>is_bool</function>,
     <function>is_real</function>,
     <function>is_int</function>,
     <function>is_integer</function>,
     <function>is_string</function>,
     <function>is_object</function>,
     <function>is_array</function>, and
     <function>is_long</function>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.is-int">
   <refnamediv>
    <refname>is_int</refname>
    <refpurpose>Find whether a variable is an integer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_int</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     This function is an alias for <function>is_long</function>.
    </simpara>
    <simpara>
     See also <function>is_bool</function>,
     <function>is_double</function>,
     <function>is_float</function>,
     <function>is_integer</function>,
     <function>is_string</function>,
     <function>is_real</function>,
     <function>is_object</function>,
     <function>is_array</function>, and
     <function>is_long</function>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.is-integer">
   <refnamediv>
    <refname>is_integer</refname>
    <refpurpose>Find whether a variable is an integer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_integer</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     This function is an alias for
     <function>is_long</function>.
    </simpara>
    <simpara>
     See also <function>is_bool</function>,
     <function>is_double</function>,
     <function>is_float</function>,
     <function>is_int</function>,
     <function>is_string</function>,
     <function>is_real</function>,
     <function>is_object</function>,
     <function>is_array</function>, and
     <function>is_long</function>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.is-long">
   <refnamediv>
    <refname>is_long</refname>
    <refpurpose>Finds whether a variable is an integer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_long</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <para>
     Returns &true; if <parameter>var</parameter> is an integer (long),
     &false; otherwise.
    </para>
    <para>
     See also <function>is_bool</function>,
     <function>is_double</function>,
     <function>is_float</function>,
     <function>is_int</function>,
     <function>is_real</function>,
     <function>is_string</function>,
     <function>is_object</function>,
     <function>is_array</function>, and
     <function>is_integer</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-numeric">
   <refnamediv>
    <refname>is_numeric</refname>
    <refpurpose>
     Finds whether a variable is a number or a numeric string
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_numeric</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <para>
     Returns &true; if <parameter>var</parameter> is a number or a
     numeric string, &false; otherwise.
    </para>
    <para>
     See also <function>is_bool</function>,
     <function>is_double</function>,
     <function>is_float</function>,
     <function>is_int</function>,
     <function>is_real</function>,
     <function>is_string</function>,
     <function>is_object</function>,
     <function>is_array</function>, and
     <function>is_integer</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-object">
   <refnamediv>
    <refname>is_object</refname>
    <refpurpose>Finds whether a variable is an object</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_object</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <para>
     Returns &true; if <parameter>var</parameter> is an object, &false;
     otherwise.
    </para>
    <para>
     See also <function>is_bool</function>,
     <function>is_long</function>,
     <function>is_int</function>,
     <function>is_integer</function>,
     <function>is_float</function>,
     <function>is_double</function>,
     <function>is_real</function>,
     <function>is_string</function>, and
     <function>is_array</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-real">
   <refnamediv>
    <refname>is_real</refname>
    <refpurpose>Finds whether a variable is a real</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_real</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     This function is an alias for <function>is_double</function>.
    </simpara>
    <simpara>
     See also <function>is_bool</function>,
     <function>is_long</function>,
     <function>is_int</function>,
     <function>is_integer</function>,
     <function>is_float</function>,
     <function>is_double</function>,
     <function>is_object</function>,
     <function>is_string</function>, and
     <function>is_array</function>.
    </simpara>
   </refsect1>
  </refentry>
  
  <refentry id="function.is-resource">
   <refnamediv>
    <refname>is_resource</refname>
    <refpurpose>
     Finds whether a variable is a resource
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_resource</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <para>
     <function>is_resource</function> returns &true; if the variable
     given by the <parameter>var</parameter> parameter is a resource, 
     otherwise it returns &false;.
    </para>
    <para>
     Resources are things like file or database result handles that
     are allocated and freed by internal PHP functions and that may
     need some cleanup when they are no longer in use but haven't been
     freed by user code.  
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-string">
   <refnamediv>
    <refname>is_string</refname>
    <refpurpose>Finds whether a variable is a string</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>bool</type><methodname>is_string</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <para>
     Returns &true; if <parameter>var</parameter> is a string,
     &false; otherwise.
    </para>
    <para>
     See also <function>is_bool</function>,
     <function>is_long</function>,
     <function>is_int</function>,
     <function>is_integer</function>,
     <function>is_float</function>,
     <function>is_double</function>,
     <function>is_real</function>,
     <function>is_object</function>, and
     <function>is_array</function>.
    </para>
   </refsect1>
  </refentry>
  
  <refentry id="function.isset">
   <refnamediv>
    <refname>isset</refname>
    <refpurpose>Determine whether a variable is set</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>int</type><methodname>isset</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     Returns &true; if <parameter>var</parameter> exists;
     &false; otherwise.
    </simpara>
    <para>
     If a variable has been unset with <function>unset</function>,
     it will no longer be <function>isset</function>.
     <informalexample>
      <programlisting role="php">
$a = "test";
echo isset ($a); // true
unset ($a);
echo isset ($a); // false
      </programlisting>
     </informalexample>
    </para>
    <simpara>
     See also <function>empty</function> and
     <function>unset</function>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.print-r">
   <refnamediv>
    <refname>print_r</refname>
    <refpurpose>
     Prints human-readable information about a variable
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>void</type><methodname>print_r</methodname>
      <methodparam><type>mixed</type><parameter>expression</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     This function displays information about the values of variables
     in a way that's readable by humans.  If given a string, integer
     or double, the value itself will be printed.  If given an array,
     values will be presented in a format that shows keys and
     elements.  Similar notation is used for objects.
    </simpara>
    <simpara>
     Compare <function>print_r</function> to
     <function>var_dump</function>.
    </simpara>
    <para>
     <informalexample>
      <programlisting role="php">
&lt;?php
$a = array (1, 2, array ("a", "b", "c"));
print_r ($a);
?>
      </programlisting>
     </informalexample>
    </para>
    <warning>
     <para>
      This function will continue forever if given an array or object 
      that contains a direct or indirect reference to itself or that 
      contains an array or object on a deeper level that does so.
      This is especially &true; for <literal>print_r($GLOBALS)</literal>, 
      as <literal>$GLOBALS</literal> is itself a global variable and
      contains a reference to itself as such.
     </para>
    </warning>
   </refsect1>
  </refentry>

  <refentry id="function.serialize">
   <refnamediv>
    <refname>serialize</refname>
    <refpurpose>
     Generates a storable representation of a value
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>string</type><methodname>serialize</methodname>
      <methodparam><type>mixed</type><parameter>value</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     <function>serialize</function> returns a string containing a
     byte-stream representation of <parameter>value</parameter> that
     can be stored anywhere.
    </simpara>
    <simpara>
     This is useful for storing or passing PHP values around without
     losing their type and structure.
    </simpara>
    <simpara>
     To make the serialized string into a PHP value again, use
     <function>unserialize</function>.    <function>serialize</function>
     handles the types <type>integer</type>, <type>double</type>,
     <type>string</type>, <type>array</type> (multidimensional) and
     <type>object</type> (object properties will be serialized, but
     methods are lost).
    </simpara>
    <para>
     <example>
      <title><function>serialize</function> example</title>
      <programlisting role="php">
// $session_data contains a multi-dimensional array with session
// information for the current user.  We use serialize() to store
// it in a database at the end of the request.

$conn = odbc_connect ("webdb", "php", "chicken");
$stmt = odbc_prepare ($conn,
      "UPDATE sessions SET data = ? WHERE id = ?");
$sqldata = array (serialize($session_data), $PHP_AUTH_USER);
if (!odbc_execute ($stmt, &amp;$sqldata)) {
    $stmt = odbc_prepare($conn,
     "INSERT INTO sessions (id, data) VALUES(?, ?)");
    if (!odbc_execute($stmt, &amp;$sqldata)) {
    /* Something went wrong.  Bitch, whine and moan. */
    }
}
      </programlisting>
     </example>
    </para>
   </refsect1>
  </refentry>
  
  <refentry id="function.settype">
   <refnamediv>
    <refname>settype</refname>
    <refpurpose>Set the type of a variable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>int</type><methodname>settype</methodname>
      <methodparam><type>string</type><parameter>var</parameter></methodparam>
      <methodparam><type>string</type><parameter>type</parameter></methodparam>
     </methodsynopsis>
    <para>
     Set the type of variable <parameter>var</parameter> to
     <parameter>type</parameter>.
    </para>
    <para>
     Possibles values of <parameter>type</parameter> are:
     <itemizedlist>
      <listitem><simpara>"integer"</simpara></listitem>
      <listitem><simpara>"double"</simpara></listitem>
      <listitem><simpara>"string"</simpara></listitem>
      <listitem><simpara>"array"</simpara></listitem>
      <listitem><simpara>"object"</simpara></listitem>
     </itemizedlist>
    </para>
    <para>
     Returns &true; if successful; otherwise returns &false;.
    </para>
    <para>
     See also <function>gettype</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.strval">
   <refnamediv>
    <refname>strval</refname>
    <refpurpose>Get string value of a variable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>string</type><methodname>strval</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     Returns the string value of <parameter>var</parameter>.
    </simpara>
    <simpara>
     <parameter>var</parameter> may be any scalar type. You cannot use
     <function>strval</function> on arrays or objects.
    </simpara>
    <simpara>
     See also <function>doubleval</function>,
     <function>intval</function>, <function>settype</function> and
     <link linkend="language.types.type-juggling">Type
     juggling</link>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.unserialize">
   <refnamediv>
    <refname>unserialize</refname>
    <refpurpose>
     Creates a PHP value from a stored representation
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>mixed</type><methodname>unserialize</methodname>
      <methodparam><type>string</type><parameter>str</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     <function>unserialize</function> takes a single serialized
     variable (see <function>serialize</function>) and converts it
     back into a PHP value.  The converted value is returned, and can
     be an <type>integer</type>, <type>double</type>,
     <type>string</type>, <type>array</type> or <type>object</type>.
     If an object was serialized, its methods are not preserved in the
     returned value.
    </simpara>
    <para>
     <example>
      <title><function>unserialize</function> example</title>
      <programlisting role="php">
// Here, we use unserialize() to load session data from a database
// into $session_data.    This example complements the one described
// with <function>serialize</function>.

$conn = odbc_connect ("webdb", "php", "chicken");
$stmt = odbc_prepare ($conn, "SELECT data FROM sessions WHERE id = ?");
$sqldata = array ($PHP_AUTH_USER);
if (!odbc_execute ($stmt, &amp;$sqldata) || !odbc_fetch_into ($stmt, &amp;$tmp)) {
    // if the execute or fetch fails, initialize to empty array
    $session_data = array();
} else {
    // we should now have the serialized data in $tmp[0].
    $session_data = unserialize ($tmp[0]);
    if (!is_array ($session_data)) {
    // something went wrong, initialize to empty array
    $session_data = array();
    }
}
      </programlisting>
     </example>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.unset">
   <refnamediv>
    <refname>unset</refname>
    <refpurpose>Unset a given variable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>int</type><methodname>unset</methodname>
      <methodparam><type>mixed</type><parameter>var</parameter></methodparam>
      <methodparam choice="opt"><type>mixed</type><parameter>var</parameter></methodparam>
      <methodparam choice="opt"><parameter>...</parameter></methodparam>
     </methodsynopsis>
    <para>
     <function>unset</function> destroys the specified variables and
     returns &true;.
    </para>
    <para>
     <example>
      <title><function>unset</function> example</title>
      <programlisting role="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);
      </programlisting>
     </example>
    </para>
    <para>
     The behavior of <function>unset</function> inside of a function
     can vary depending on what type of variable you are attempting to
     destroy.
    </para>
    <para>
     If a globalized variable is <function>unset</function> inside of
     a function, only the local variable is destroyed.  The variable
     in the calling environment will retain the same value as before
     <function>unset</function> was called.
     <informalexample>
      <programlisting role="php">
function destroy_foo() {
    global $foo;
    unset($foo);
}

$foo = 'bar';
destroy_foo();
echo $foo;
      </programlisting>
     </informalexample>
     The above example would output:
     <informalexample>
      <programlisting>
bar
      </programlisting>
     </informalexample>
    </para>
    <para>
     If a variable that is PASSED BY REFERENCE is
     <function>unset</function> inside of a function, only the local
     variable is destroyed.  The variable in the calling environment
     will retain the same value as before <function>unset</function>
     was called.
     <informalexample>
      <programlisting role="php">
function foo(&amp;$bar) { 
    unset($bar); 
    $bar = "blah"; 
}

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

foo($bar);
echo "$bar\n";
      </programlisting>
     </informalexample>
     The above example would output:
     <informalexample>
      <programlisting>
something
something
      </programlisting>
     </informalexample>
    </para>
    <para>
     If a static variable is <function>unset</function> inside of a
     function, <function>unset</function> unsets the reference to the
     static variable, rather than the static variable itself.
     <informalexample>
      <programlisting role="php">
function foo() { 
    static $a;
    $a++;
       echo "$a\n";

    unset($a);
}

foo();
foo();
foo();
      </programlisting>
     </informalexample>
     The above example would output:
     <informalexample>
      <programlisting>
1
2
3
      </programlisting>
     </informalexample>
    </para>
    <para>
     If you would like to <function>unset</function> a global variable inside of a function, you can use the <parameter>$GLOBALS</parameter> array to do so:
     <informalexample>
      <programlisting role="php">
function foo() {
    unset($GLOBALS['bar']);       
}

$bar = "something";
foo();
      </programlisting>
     </informalexample>
    </para>
    <para>
     See also <function>isset</function> and
     <function>empty</function>.
    </para>
   </refsect1>
  </refentry>
  
  <refentry id="function.var-dump">
   <refnamediv>
    <refname>var_dump</refname>
    <refpurpose>Dumps information about a variable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
     <methodsynopsis>
      <type>void</type><methodname>var_dump</methodname>
      <methodparam><type>mixed</type><parameter>expression</parameter></methodparam>
     </methodsynopsis>
    <simpara>
     This function returns structured information about an expression
     that includes its type and value.  Arrays are explored
     recursively with values indented to show structure.
    </simpara>
    <simpara>
     Compare <function>var_dump</function> to
     <function>print_r</function>.
    </simpara>
    <para>
     <informalexample>
      <programlisting role="php">
&lt;pre>
&lt;?php
    $a = array (1, 2, array ("a", "b", "c"));
    var_dump ($a);
?>
&lt;/pre>
      </programlisting>
     </informalexample>
    </para>
   </refsect1>
  </refentry>

 </reference>

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