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

Porting to HP Fortran
Chapter 11238
In practice, however, programming is rarely so simple. Many Fortran programs have a long history and were
originally coded at a time when portability was not a concern because many programs were written to
execute on one platform only. Older Fortran programs—so-called dusty-deck programs—are likely to have
passed through different dialects of Fortran, picking up features from each, even after those features have
become outmoded. Porting such a program may sometimes be as simple as identifying and removing the
nonportable features. But more often than not, it involves finding ways to implement the functionality of the
nonportable features.
To make the task of porting easier, HP Fortran includes the following features:
• Language extensions—statements, data types, directives, and intrinsic functions—that are compatible
with other Fortran implementations.
• Compile-line options to help with the porting process.
This chapter includes the following sections:
• Compatibility extensions
• Using porting options
NOTE For information about migrating HP FORTRAN 77 programs to HP
Fortran, refer to “Migrating to HP Fortran” on page 219.