Fortran Interface to C Array of Pointer to void and Opaque Struct

Help
1

What would be the Fortran interface to these two items:

struct m_{
  int filesize[some_value]
  void* filedata[some_value]
}m
  1. In GLFW, there is an opaque struct:

typedef struct GLFWwindow GLFWwindow;

For 1, I currently have:

type, bind(c) :: m
  integer(c_int) :: filesize(some_value)
  type(c_ptr) :: filedata
end type m

I am worried about losing the dimension of filedata.

For 2, I have an empty derived type:

type, bind(c) :: GLFWwindow
end type GLFWwindow

That the type is empty worries me and does indeed produce a warning.

2 
  void* filedata[some_value];  // Note, both struct members should end with ;

This is an array of void pointers. So why not

type, bind(c) :: m
  integer(c_int) :: filesize(some_value)
  type(c_ptr) :: filedata(some_value)
end type m
3

@general_rishkin , can you please share the declaration of some_value on the C side?

4

Thanks @msz59 . This is what I tried initially but for some reason, it did not compile.

I have just tried it again now and it does compile. Strange. I must have had it mixed up with something else.

5

@FortranFan , the declaration is :

#define some_value 2000

However, I think I was getting confused because the first time I tried type(c_ptr) :: filedata(some_value), I got an error. Hence, my creating this topic post. It compiles now.