HP Fortran Programmer's Guide (March 2010)

Migrating to HP Fortran
Migration issues
Chapter 10 235
Migration issues
Migration issues fall into four general categories:
• Source code issues
• Command-line option issues
•Object code issues
• Data file issues
Source code issues
For standard-conforming HP FORTRAN 77 code, migration to HP Fortran can be as simple as
recompiling with the f90 command. The f90 command accepts source files with the
extensions .f and .F (among others).
However, source code is likely to be the main obstacle on the migration path to HP Fortran.
The reason is that HP FORTRAN 77 supports a number of compiler directives and intrinsic
functions, some of which are supported by HP Fortran, but others of which are either
unsupported or have changed. The following sections discuss how to change directives and
intrinsics when migrating HP FORTRAN 77 source code to HP Fortran.
NOTE HP FORTRAN 77 accepts (or forgives) a number of common but nonstandard
programming practices that HP Fortran does not. These nonstandard practices
as well as all known incompatibilities between HP FORTRAN 77 and
HP Fortran are listed in “Incompatibilities with HP FORTRAN 77” on
page 229.
Directives
HP FORTRAN 77 supports more than seventy directives; of these, only a handful are
supported by HP Fortran; see “Directives” on page 233, for the directives that are supported
and for the new directive syntax. Note that, except for the LIST directive, the HP Fortran
directives have more limited functionality than their HP FORTRAN 77 counterparts; see the
HP Fortran Programmer's Reference.