HP 3000 Manuals HP 3000 Manuals
Appendix C Using HP Link Editor/XL with HP FORTRAN 77/XL
This appendix discusses the HP FORTRAN 77/XL compiler conventions that
relate specifically to HP Link Editor/XL. The following items explain how
you use these conventions to successfully create executable program
files. (For details about the compiler conventions shown, see the HP
FORTRAN 77/XL Reference Manual.)
* Compilation units
If you do not use the $RLFILE compiler directive, the entire
source file is treated as one compilation unit and the compiler
produces a relocatable object file containing a single relocatable
object module.
If you use $RLFILE, each program unit (main program, subroutine,
function, or block data subprogram) is treated as a separate
compilation unit and results in a separate relocatable object
module in the relocatable library.
* Relocatable object module name
If you do not use the $RLFILE compiler directive, the relocatable
object module name is the unqualified name of the HP FORTRAN 77
source file.
If you use $RLFILE, the relocatable object module name is the name
of that program unit or module. If the program is a block data
subprogram, you must use the BLOCKDATA parameter (not the MODULE
parameter) to reference it when using the link editor.
* Program entry point
The program entry point is the first executable statement in the
main program. This name is main__ unless you enter a different
name in the HP FORTRAN 77 program statement.
* Scope of variables, functions and procedures
Names of COMMON blocks, subroutines and functions have universal
scope. When compiled separately, HP FORTRAN 77 subroutines and
functions do not generate a dummy main block.
* Locality sets
The HP FORTRAN 77 $LOCALITY compiler directive associates program
units with a locality set. The name of the locality set must
begin with a letter. It can contain up to 32 alphanumeric
characters. Place the $LOCALITY directive before the program
unit(s) to be placed in a locality set (the directive remains in
effect until the next $LOCALITY directive).
If you do not use the $LOCALITY directive, CODE is the default
locality set name.
* Type checking
Two compiler directives specify the level of type checking that
the link editor uses when resolving references between HP FORTRAN
77 subroutines and functions. They are $CHECK_FORMAL_PARM and
$CHECK_ACTUAL_PARM and they are described in the next two
paragraphs.
$CHECK_FORMAL_PARM associates a check level with the formal
declaration of the subroutine or function. Place
$CHECK_FORMAL_PARM before the declaration of the subroutine or
function (it remains in effect until a new directive is
encountered). If you do not use $CHECK_FORMAL_PARM, the compiler
uses type checking level 3.
$CHECK_ACTUAL_PARM associates a check level with each subroutine
or function call encountered. You can place $CHECK_ACTUAL_PARM
anywhere in the source file. It remains in effect until a new
directive is encountered. If you do not use $CHECK_ACTUAL_PARM,
the compiler uses type checking level 3.
To override the type checking level used during compilation, use
the PARMCHECK option of the LINK command (see Chapter 4).