16.4 Association

Entities are associated when each is associated with the same storage location.

Two (or more) entities can become associated by the following:

• Name association

• Pointer association

• Storage association

Example 16-1 shows name, pointer, and storage association between an external program unit and an external procedure.

Example 16-1 Example of Name, Pointer, and Storage Association

! Scoping Unit 1: An external program unit

REAL A, B(4)
REAL, POINTER :: M(:)
REAL, TARGET :: N(12)
COMMON /COM/...
EQUIVALENCE (A, B(1))         ! Storage association between A and B(1)
M => N                        ! Pointer association
CALL P (actual-arg,...)
...

! Scoping Unit 2: An external procedure
SUBROUTINE P (dummy-arg,...)  ! Name and storage association between
                              !    these arguments and the calling
                              !    routine's arguments in scoping unit 1

  COMMON /COM/...             ! Storage association with common block COM
                              !    in scoping unit 1
  REAL Y
  CALL Q (actual-arg,...)
  CONTAINS
    SUBROUTINE Q (dummy-arg,...) ! Name and storage association between
                                 !   these arguments and the calling
                                 !   routine's arguments in host procedure
                                 !   P (subprogram Q has host association
                                 !   with procedure P)
      Y = 2.0*(Y-1.0)         ! Name association with Y in host procedure P
    ...