echo "<pre>";
print_r(get_declared_classes());
echo "</pre>";
/*
run:
Array
(
[0] => stdClass
[1] => Exception
[2] => ErrorException
[3] => Closure
[4] => DateTime
[5] => DateTimeZone
[6] => DateInterval
[7] => DatePeriod
[8] => LogicException
[9] => BadFunctionCallException
[10] => BadMethodCallException
[11] => DomainException
[12] => InvalidArgumentException
[13] => LengthException
[14] => OutOfRangeException
[15] => RuntimeException
[16] => OutOfBoundsException
[17] => OverflowException
[18] => RangeException
[19] => UnderflowException
[20] => UnexpectedValueException
[21] => RecursiveIteratorIterator
[22] => IteratorIterator
[23] => FilterIterator
[24] => RecursiveFilterIterator
[25] => CallbackFilterIterator
[26] => RecursiveCallbackFilterIterator
[27] => ParentIterator
[28] => LimitIterator
[29] => CachingIterator
[30] => RecursiveCachingIterator
[31] => NoRewindIterator
[32] => AppendIterator
[33] => InfiniteIterator
[34] => RegexIterator
[35] => RecursiveRegexIterator
[36] => EmptyIterator
[37] => RecursiveTreeIterator
[38] => ArrayObject
[39] => ArrayIterator
[40] => RecursiveArrayIterator
[41] => SplFileInfo
[42] => DirectoryIterator
[43] => FilesystemIterator
[44] => RecursiveDirectoryIterator
[45] => GlobIterator
[46] => SplFileObject
[47] => SplTempFileObject
[48] => SplDoublyLinkedList
[49] => SplQueue
[50] => SplStack
[51] => SplHeap
[52] => SplMinHeap
[53] => SplMaxHeap
[54] => SplPriorityQueue
[55] => SplFixedArray
[56] => SplObjectStorage
[57] => MultipleIterator
[58] => ReflectionException
[59] => Reflection
[60] => ReflectionFunctionAbstract
[61] => ReflectionFunction
[62] => ReflectionParameter
[63] => ReflectionMethod
[64] => ReflectionClass
[65] => ReflectionObject
[66] => ReflectionProperty
[67] => ReflectionExtension
[68] => ReflectionZendExtension
[69] => SessionHandler
[70] => __PHP_Incomplete_Class
[71] => php_user_filter
[72] => Directory
[73] => ZipArchive
[74] => LibXMLError
[75] => DOMException
[76] => DOMStringList
[77] => DOMNameList
[78] => DOMImplementationList
[79] => DOMImplementationSource
[80] => DOMImplementation
[81] => DOMNode
[82] => DOMNameSpaceNode
[83] => DOMDocumentFragment
[84] => DOMDocument
[85] => DOMNodeList
[86] => DOMNamedNodeMap
[87] => DOMCharacterData
[88] => DOMAttr
[89] => DOMElement
[90] => DOMText
[91] => DOMComment
[92] => DOMTypeinfo
[93] => DOMUserDataHandler
[94] => DOMDomError
[95] => DOMErrorHandler
[96] => DOMLocator
[97] => DOMConfiguration
[98] => DOMCdataSection
[99] => DOMDocumentType
[100] => DOMNotation
[101] => DOMEntity
[102] => DOMEntityReference
[103] => DOMProcessingInstruction
[104] => DOMStringExtend
[105] => DOMXPath
[106] => PDOException
[107] => PDO
[108] => PDOStatement
[109] => PDORow
[110] => PharException
[111] => Phar
[112] => PharData
[113] => PharFileInfo
[114] => SimpleXMLElement
[115] => SimpleXMLIterator
[116] => XMLReader
[117] => XMLWriter
[118] => finfo
[119] => mysqli_sql_exception
[120] => mysqli_driver
[121] => mysqli
[122] => mysqli_warning
[123] => mysqli_result
[124] => mysqli_stmt
[125] => SQLite3
[126] => SQLite3Stmt
[127] => SQLite3Result
[128] => XSLTProcessor
)
*/
