What's the difference between a pointer, and a pointer variable?

c, function-pointers

Solution

The difference between a pointer value and a pointer variable is illustrated by:

int swap_int(int *i1, int *i2)
{
    int t = *i1;
    *i1 = *i2;
    *i2 = t;
}

int main(void)
{
    int  v1 = 0;
    int  v2 = 37;
    int *p2 = &v2;
    printf("v1 = %d, v2 = %d\n", v1, v2);
    swap_int(&v1, p2);
    printf("v1 = %d, v2 = %d\n", v1, v2);
    return 0;
}

Here, `p2` is a pointer variable; it is a pointer to `int`. On the other hand, in the call to `swap_int()`, the argument `&v1` is a pointer value, but it is in no sense a pointer variable (in the calling function). It is a pointer to a variable (and that variable is `v1`), but simply writing `&v1` is not creating a pointer variable. Inside the called function, the value of the pointer `&v1` is assigned to the local pointer variable `i1`, and the value of the pointer variable `p2` is assigned to the local pointer variable `i2`, but that's not the same as saying `&v1` is a pointer variable (because it isn't a pointer variable; it is simply a pointer value).

However, for many purposes, the distinction is blurred. People would say '`p2` is a pointer' and that's true enough; it is a pointer variable, and its value is a pointer value, and `*p2` is the value of the object that `p2` points to. You get the same blurring with '`v1` is an `int`'; it is actually an `int` variable and its value is an `int` value.

Problem

I know this is very basic but it is little bit confusing to me. I've read: a pointer is nothing more than an address, and a pointer variable is just a variable that can store an address. When we store the address of a variable `i` in the pointer variable `p`, we say that `p` points to `i`. ``` int i, *p = &i; ``` `p` points to `i`. To gain access to the object that a pointer points to, we use the `*` (indirection) operator. If `p` is a pointer then `*p` represents the object to which `p` currently points. Now I am confused that what should I call `p` -- pointer or pointer variable? Additional: Is a pointer always the same as an address?

Original source

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