Definition of struct timeout_cb get warning

[ygj6]

In Xcode, The definition of struct timeout_cb in timeout.h

struct timeout_cb {
	void (*fn)();
	void *arg;
}; /* struct timeout_cb */

In this line

void (*fn)();

I get a warning "This function declaration is not a prototype Insert 'void'". Can you add a "void" as this:

void (*fn)(void);