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

Migrating to HP Fortran
Migration issues
Chapter 10 227
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 221.
Directives
HP FORTRAN 77 supports more than seventy directives; of these, only a handful are supported by
HP Fortran; see “Directives” on page 225, 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.