Re: still no success binding DLL's callback function

[moerm]

Here is your problem:
    
    
    Fl_Callback* = proc(widget: ptr Fl_Widget, pData: ptr any)
    
    # ...
    proc ButtonClick (button: ptr FL_WIDGET, arg: ptr any):**cint  {.cdecl.}** =
    
    Run

In other words, `Fl_Callback` is not cdecl and its return type is void while 
`ButtonClick` is cdecl and its return type is cint.