Pointer Aliases

Two pointers can refer to the same object, so writing through one pointer changes what the other reads.

pointer_aliases.c

#include <stdio.h>

int main(void) {
    int value = ;
    int *left = &value;
    int *right = left;

    *right = *right + 1;

    printf("left=%d value=%d\n", *left, value);
    return 0;
}

#include <stdio.h>

int main(void) {
    int value = ;
    int *left = &value;
    int *right = left;

    *right = *right + 1;

    printf("left=%d value=%d\n", *left, value);
    return 0;
}

#include <stdio.h>

int main(void) {
    int value = ;
    int *left = &value;
    int *right = left;

    *right = *right + 1;

    printf("left=%d value=%d\n", *left, value);
    return 0;
}

alias Pointers alias when they store the same address.

shared object A write through one alias updates the single shared object.