Record Structures

The record structure was defined in earlier versions of Compaq Fortran as a language extension. It is still supported in Visual Fortran, although its functionality has been replaced by standard Fortran 95/90 derived types. Record structures in existing code can be easily converted to Fortran 95/90 derived type structures for portability, but can also be left in their old form. In most cases, a Compaq Fortran record and a Fortran 95/90 derived type can be used interchangeably.

Compaq Fortran record structures are similar to Fortran 95/90 derived types.

A record structure is an aggregate entity containing one or more elements. (Record elements are also called fields or components.) You can use records when you need to declare and operate on multi-field data structures in your programs.

Creating a record is a two-step process:

1. You must define the form of the record with a multistatement structure declaration.
   
   
2. You must use a RECORD statement to declare the record as an entity with a name. (More than one RECORD statement can refer to a given structure.)

Examples

Compaq Fortran record structures, using only intrinsic types, easily convert to Fortran 95/90 derived types. The conversion can be as simple as replacing the keyword STRUCTURE with TYPE and removing slash ( / ) marks. The following shows an example conversion:

STRUCTURE /employee_name/
  CHARACTER*25  last_name
  CHARACTER*15  first_name
END STRUCTURE
STRUCTURE /employee_addr/
  CHARACTER*20  street_name
  INTEGER(2)    street_number
  INTEGER(2)    apt_number
  CHARACTER*20  city
  CHARACTER*2   state
  INTEGER(4)    zip
END STRUCTURE

TYPE employee_name
  CHARACTER*25  last_name
  CHARACTER*15  first_name
END TYPE
TYPE employee_addr
  CHARACTER*20  street_name
  INTEGER(2)    street_number
  INTEGER(2)    apt_number
  CHARACTER*20  city
  CHARACTER*2   state
  INTEGER(4)    zip
END TYPE

STRUCTURE /employee_data/
  RECORD  /employee_name/ name
  RECORD  /employee_addr/ addr
  INTEGER(4) telephone
  INTEGER(2) date_of_birth
  INTEGER(2) date_of_hire
  INTEGER(2) social_security(3)
  LOGICAL(2) married
  INTEGER(2) dependents
END STRUCTURE

TYPE employee_data
  TYPE (employee_name) name
  TYPE (employee_addr) addr
  INTEGER(4) telephone
  INTEGER(2) date_of_birth
  INTEGER(2) date_of_hire
  INTEGER(2) social_security(3)
  LOGICAL(2) married
  INTEGER(2) dependents
END TYPE

• Structure Declarations
• RECORD Statement
• References to Record Fields
• Aggregate Assignment