[XForms] fl_set_form_callback problem

[vwf]

Hello,

I have a problem with arguments.  XForms has a routine
fl_set_object_callback that is defined like:

void fl_set_form_callback(FL_FORM *form,
        void (*callback)(FL_OBJECT *, void *),
        void *data);

In my old program, that is in the process of rewriting, I bound:
        fl_set_form_callback(thisone, LogState, 0);

I cannot make the compiler stop warning when I try to bind the callback
in my reworked program. Who knows the correct way?

Thank you,
Frits