questions about pointers

hey guys, im kind of new in c and i have two questions, first what is the void * v[] for? second what is the "comp" in this line? "int (*comp)(void *,void *);" its part of an example program for qsort...is it casting of some kind?
appreciate any help.

1) It is an array of pointers that point to a void (can point to anything). So v[1] is a pointer, v[3] is also a pointer (a *void)
2) It is a function pointer that points to a function that is like int fun(void *, void* )
Example:

Code:

---

int fun(void* a, void* b)
{
  ...
  return 0;
}

int (*comp)(void*, void*);

comp = &fun; //comp will point to fun
comp(a, b); //like fun(a,b)

---

comp is a pointer to a function returning int
v is an array of void pointers

"int (*comp)(void *,void *);" is a function pointer. One use for that is so you can include a function as a parameter to another function:

Code:

---

#include <stdio.h>

void one() {
        printf("Function one\n");
}

void two() {
        printf("Function two\n");
}

void dowhat (void (somefunction)()) {
        somefunction();
}

int main() {
        dowhat(one);
        dowhat(two);
        return 0;
}

---

I've never used C's qsort but apparently you can pass it your own comparison function, which accepts two pointers (to the things to compare) and returns an int.