Class is passed as a character string with a leading two-byte binary length field. The length is the number of bytes in the class name, excluding the length field itself and any additional unused bytes in the field at the end of the name. See Understanding binder programming concepts for a definition of classes in program objects, and a list of commonly used class names. B_PMAR is also accepted as a class name for the GD call, although it is not an actual class in a binder workmod.