HP Fortran Programmer's Guide (B3908-90031; September 2011)

Using Fortran directives
Using HP Fortran directives
Chapter 9 209
The following sections describe each of the HP Fortran directives.
$HP$ ALIAS
The ALIAS directive associates the name of a subroutine, function, entry, or common block with an external
name and specifies the parameter-passing conventions of routines written in other languages.
Syntax
!$HP$ ALIAS name [= external-name ] [(arg-pass-mode-list)]
name
is the name used by the program to refer to a subroutine, function, or procedure entry
point—but not to an internal subroutine. If name is enclosed by slashes, it is a common
block name.
external-name
is a character constant that specifies a standard symbolic name.
arg-pass-mode-list
is used only when name is that of a procedure that takes arguments. The items in the list
specify how the corresponding actual argument are to be passed. The items can be
either of the following built-in functions:
• %VAL: pass the value of the actual argument
• %REF: pass the address of the actual argument
There must be as many items in the list as there are arguments in the procedure, they
must be separated by commas, and they must correspond positionally to the arguments.
Description and restrictions
The $HP$ ALIAS directive serves two purposes:
• It provides a way to associate the name used by your program when referring to a subroutine, function,
entry, or common block with a distinct external name. This feature is especially useful when you want
to access a variety of different graphics device drivers from the same source code so that different
hardware configurations can be supported.
• When used in conjunction with the %VAL and %REF built-in functions, it provides a way to direct the
compiler to use the appropriate parameter passing conventions to communicate with routines written in
other high-level languages.