gerph Writing Fortran for RISC OS
Use this skill for Fortran work in the RISC OS build environment.
Read only the reference files needed for the task:
- Build, source layout, modules, and command lines:
references/building.md - C/Fortran interworking, C strings, and
_kernel_swi_regs:references/c-interop.md - Generated constants and Fortran modules from RISC OS headers:
references/generated-constants.md - Common RISC OS build pitfalls and review checks:
references/pitfalls.md
Core Rules
Fortran source files live in f90/ and do not have a .f90 suffix in the
host filesystem. Use RISC OS-style names with the wrappers, for example:
riscos64-fortran -c -o o.name f90.name
riscos64-link o.name -lgfortran -o name,ff8
Always link -lgfortran when any Fortran object is present.
Always use implicit none in every program, module, function, and
subroutine.
Use modules for shared constants and library code. Fortran module names are
flat; there is no use riscos/WimpSpace path syntax. Prefer namespaced module
names such as riscos_wimpspace.
For C-facing interfaces, use iso_c_binding and bind(C, name="...").
Use value in Fortran for scalar arguments passed by value from C.
For _kernel_swi_regs, C regs.r[0] maps to Fortran regs(1).
Do not read or write generated .rotransform files.