HP Fortran Programmer's Reference (September 2007)

Program units and procedures
Procedure interface
Chapter 7182
Interface blocks
An interface block is used to provide an explicit interface for external procedures or to
define a generic procedure. An interface block may appear in any program unit, except a block
data program unit. It is specified in the specification part of the program unit.
The syntax for an interface block is:
INTERFACE [ generic-spec ]
[ interface-body ]...
[MODULE PROCEDURE module-procedure-name-list ]
END INTERFACE
generic-spec
is one of:
• generic-name
• OPERATOR ( operator )
• ASSIGNMENT (=)
If generic-spec is omitted, then the MODULE PROCEDURE statement must
also be omitted.
generic-name
is the name of the generic procedure that is referenced in the subprogram
containing the interface block.
operator
is a unary or binary operator—intrinsic or user-defined—of the form:
. letter [ letter ]... .
interface-body
is:
function-statement
[ specification-part ]
end-function-statement
or
subroutine-statement
[ specification-part ]
end-subroutine-statement
module-procedure-name-list