(PHP 5 >= 5.1.3, PHP 7)
ReflectionExtension::getDependencies — Gets dependencies
Gets dependencies, by listing both required and conflicting dependencies.
This function has no parameters.
   An associative array with dependencies as keys and
   either Required, Optional 
   or Conflicts as the values.
  
Example #1 ReflectionExtension::getDependencies() example
<?php
$dom = new ReflectionExtension('dom');
print_r($dom->getDependencies());
?>
The above example will output something similar to:
Array
(
    [libxml] => Required
    [domxml] => Conflicts
)