PHP outputs all variables, constants, modules, functions, and classes of the current process

echo '';

$b = array(1,1,2,3,5,8);

$arr = get_defined_vars();

/ / Print $b
print_r($arr["b"]);

// Print all server variables
print_r($arr["_SERVER"]);

// Print all available key values ​​​​of the variable array
print_r (array_keys(get_defined_vars()));
?>

2. get_defined_functions (PHP 4 >= 4.0.4, PHP 5) — Get all defined functions array get_defined_functions (void) //void means empty and does not require any parameters

echo '';

function foo()
{
echo "This is my function foo";
}
$arr = get_defined_functions();
print_r( $arr);

?>

3. get_loaded_extensions (PHP 4, PHP 5) — Get all available modules

echo '';
print_r(get_loaded_extensions());
(PHP 4, PHP 5) — Get the available functions of the specified module
array get_extension_funcs (string $module_name) This function returns all available functions of the specified module. The parameters passed in (module names) must be lowercase

echo '

';  print_r(get_extension_funcs("gd")); <div class="blockcode">print_r(get_extension_funcs("xml")); <div id="code_mKb">?><ol>
<li> </li>
<li>Copy Code </li>
<li>
<li>
<li>
<li>5. get_defined_constants
</li>
<li> (PHP 4 >= 4.1.0, PHP 5) — Get the names of all constants in an associative array and their values
array get_defined_constants ([ bool $categorize = false ] )
 </li>
</ol>
</div>
<em onclick="copycode($('code_mKb'));"></em>
</div><p><?php <strong>echo '</p><pre class="brush:php;toolbar:false">';  define("MY_CONSTANT", 1); <div class="blockcode">print_r(get_defined_constants(true)); <div id="code_GCV">?><ol>
<li>
<li>Copy code</li>
<li> </li>
<li> </li>
<li>
<li>6. get_declared_classes
</li>
<li> (PHP 4, PHP 5) — Get an array consisting of the names of defined classes
array get_declared_classes ( void )
 </li>
</ol>
</div>
<em onclick="copycode($('code_GCV'));"></em>
</div><p><?php <strong>echo '</p><pre class="brush:php;toolbar:false">';  //define classone <div class="blockcode">class classone { } <div id="code_S7D"> <ol>//define classtwo <li>class classtwo { } </li>
<li> </li>
<li>//This will show X classes (built-ins, extensions etc) with </li>
<li>//classone and classtwo as the last two elements </li>
<li> </li>
<li>print_r(get_declared_classes()); </li>
<li> </li>
<li>//define classthree </li>
<li>class classthree { } </li>
<li> </li>
<li>//...and four </li>
<li> class classfour { } </li>
<li> </li>
<li>//Shows the same result as before with class three and four appended </li>
<li>print_r(get_declared_classes()); </li>
<li>?> </li>
<li>
<li>
<li>Copy code</li>
<li>
<li>
<li>
<li>
<li>


</li>
</ol>
</div>
<em onclick="copycode($('code_S7D'));">

</em>
</div>