HP 3000 Manuals

HP FORTRAN 77/iX Reference

Files 

A FORTRAN unit number cannot be passed to a non-FORTRAN subprogram to
perform input/output on the associated file.  Similarly, file variables
of a non-FORTRAN program cannot be passed to a FORTRAN program to enable
file access.  However, a file can always be accessed by using system
intrinsics.  Support for such access is provided by the FSET and FNUM
intrinsics, described in chapter 5, "File Handling".

MPE/iX 5.0 Documentation