Example of interfacing a fortran code with a c++ driver
gfortran -c global.f95
g++ -c main.cpp
g++ -o main global.o main.o -lgfortran
main.cpp contains the main driver of the code. It calls a fortran init subroutine on every subdomain, and receives a pointer to an instance of a data structure defined in global_data_module.f95. These pointers can be passed around on the c++ side of the code. In order to extract values from the data structure (for boundary value exchange, for instance) we can pass the address of this data structure into a fortran subroutine and pass back data as scalar values or c-style arrays.
The subroutines inside cwrappers.f95 are called from the C code, use the ISO c-bindings to translate the pointers from C to Fortran (and back) and then call the appropriate subroutine.
Several subroutines contain code that was essentially just copied and pasted from the ADCIRC source code. read_fort14.f95 is basically exactly the same as the analogous portion of the ADCIRC code, but as you can see, when we want to write to (or read from) members of the global data type, we have to prepend g% to the variable name.
We believe this approach will allow us to use almost all of the current fortran code and interface it with HPX and LGD in a threadsafe fashion. This code was tested in a multi-threaded HPX environment (although that code isn't in this repository) and as far as we can tell it seems to be thread safe.
Input files were created using adcprep, but due to some file reading issues, I manually cropped the PE****/fort.18 files up to the RESNODE lines. The included mesh files in the folder "shin32" should work. Incidentally, the locations of all the input files are all hard-coded into the executable.
To run the code, you also need to create a directory called "output", or it will complain about not being able to open output files.