# Use and Host Association Overview

Use association allows the entities in a module to be accessible to other scoping units. Host association allows the entities in a host scoping unit to be accessible to an internal subprogram, a module subprogram, or submodule program.

Use association and host association remain in effect throughout the execution of the executable program.

An interface body does not access named entities by host association, but it can access entities by use association.

## Examples

The following example shows host and use association:

     MODULE SHARE_DATA
       REAL Y, Z
     END MODULE

     PROGRAM DEMO
       USE SHARE_DATA         ! All entities in SHARE_DATA are available
       REAL B, Q              !   through use association.
       ...
       CALL CONS (Y)
     CONTAINS
       SUBROUTINE CONS (Y)    ! Y is a local entity (dummy argument).
         REAL C, Y
         ...
         Y = B + C + Q + Z    ! B and Q are available through host association.
         ...                  !   C is a local entity, explicitly declared.
       END SUBROUTINE CONS    !   is available through use association.
     END PROGRAM DEMO

## See Also

Use Association
Host Association
Scope for details on entities with local scope