Function is really a macro or function pointer

When wrapping a C library, a function which is really a macro may not create a C wrapper. It is necessary to use the option C_force_wrapper: true to create a wrapper which will expand the macro and create a function which the Fortran wrapper may call. This same issue occurs when the function is really a function pointer.

When wrapping C++, a C wrapper is always created to create a extern C symbol that Fortran can call. So this problem does not occur.

F_name_impl with fortran_generic

Using the F_name_impl format string to explicitly name a Fortran wrapper combined with the fortran_generic field may present some surprising behavior. The routine BA_change takes a long argument. However, this is inconvenient in Fortran since the default integer is typically an int. When passing a constant you need to explicitly state the kind as 0_C_LONG. Shroud lets you create a generic routine which will also accept 0. But if you explicitly name the function using F_name_impl, both Fortran generated functions will have the same name. The solution is to set format field F_name_generic and the option for F_name_impl_template.

- decl: int BA_change(const char *name, long n)
    F_name_generic: change
    F_name_impl_template: "{F_name_generic}{function_suffix}"
  - decl: (int n)
    function_suffix: int
  - decl: (long n)
    function_suffix: long

Will generate the Fortran code

interface change
    module procedure change_int
    module procedure change_long
end interface change