qsort:强制转换比较器函数本身还是在比较器函数体中转换参数？

void qsort(void *base, size_t num, size_t size, int (*compar)(const void *, const void *));

int compar(const void *a, const void *b);

int compare_int(const void *a, const void *b) {
    int int_a = *(int *)a;
    int int_b = *(int *)b;
    return int_a - int_b;
}

int main() {
    int arr[] = {3, 1, 4, 1, 5, 9};
    qsort(arr, sizeof(arr) / sizeof(arr[0]), sizeof(int), (int (*)(const void *, const void *))compare_int);
    return 0;
}

int compare_int(const void *a, const void *b) {
    int int_a = *(int *)a;
    int int_b = *(int *)b;
    return int_a - int_b;
}

int main() {
    int arr[] = {3, 1, 4, 1, 5, 9};
    qsort(arr, sizeof(arr) / sizeof(arr[0]), sizeof(int), compare_int);
    return 0;
}