HPF is the default language assumption. It requires no MAP_TO, LAYOUT, or PASS_BY attributes in explicit interface definitions. All required subprogram binding information can be accomplished via the standard Fortran explicit interface.
The rules stated in section 14.7 of the Fortran standard will apply to variables defined in Fortran-based SERIAL and LOCAL scoping units. In particular, if the definition status, association status, or allocation status of a variable is defined upon execution of a RETURN statement or an END statement in a Fortran subprogram, such a variable in an SERIAL or LOCAL subprogram will be defined upon execution of a RETURN statement or an END statement.
Any I/O performed within an extrinsic subprogram of a different model, and the correspondence between file names and unit numbers used in global HPF and those used in local or serial subprogram code will be implementation defined.