Valgrind legitimate “possibly lost” bytes example

Question

I saw that valgrind classifies memory leaks into:

• definitely lost
• indirectly lost
• possibly lost
• still reachable

Answer 1

char *p = malloc(100);
if (p != 0)
{
    p += 50;
    /* at this point, no pointer points to the start of the allocated memory */
    /* however, it is still accessible */
    for (int i = -50; i != 50; i++)
        p[i] = 1;
    free (p - 50);
}