Thread: Identifying size of structure arrays

I would like to receive an unknown array of structures as a parameter in a function and identify how many arrays of that structure have been passed? How do I do it?

For e.g,

struct tag1 {
char fld1 [10];
char fld2[10];
};

struct tag1 st[10];

main()
{
func1(st);
}

func1(struct tag1 *ptr)
{
// how do I identify here that there are 10 arrays of this
// structure???
}