Access Type: Access type allows to manipulate data, which are created dynamically during simulation and which exact size is not known in advance. Any reference to them is performed via allocators, which work in a similar way as pointers in programming languages. Simplified Syntax access subtype_indication type identifier; Here, the subtype_indication denotes the type of an object designated by a value of an access type. It can be any scalar, composite or other access type. File type is not allowed here. Variables are only the objects allowed to be of the access type. The default value of an access type is null. NULL  designates no object at all. Allocators has to be used to assign any other value to an object of an access type. The access type allows to create recursive data structures