Open Watcom FORTRAN 77 Language Reference

Structures, Unions and Records
PARAMETER (MAX_ELS=1000)
STRUCTURE /OBJECT/
REAL SIZE
INTEGER WEIGHT
CHARACTER*2 COLOUR
END STRUCTURE
RECORD /OBJECT/ ITEM(MAX_ELS)
To read or write the attributes relating to an object, you would use a statement such as:
READ(UNIT=3) ITEM(I)
6.3 Unions
Sometimes it is useful to be able to describe parts of structures in different ways in much the same way that
the EQUIVALENCE statement is used to describe a specific storage area in different ways. The UNION -
END UNION statements are used to mark a section of a structure that will have alternate storage
organizations (MAPs). The MAP - END MAP statements are used to define the start and end of an alternate
storage map. Thus several MAP - END MAP pairs will appear between a UNION - END UNION section.
Consider the following example. The subroutine displays the contents of a field using different names and
formats depending on a TYPE field.
Example:
Unions 169