How does C free() work?
- by slee
#include <stdio.h>
#include <stdlib.h>
int * alloc()
{
int *p = (int *)calloc(5,4);
printf("%d\n",p);
return p;
}
int main()
{
int *p = alloc();
free(p);
printf("%d\n",p);
p[0] = 1;
p[1] = 2;
printf("%d %d\n",p[0],p[1]);
}
As to the code segment, I allocate 5 ints,first. And then I free the memory.
When I printf p, why does p sill have a value same to the memory address allocated first?
And I also can assign value to p[0] and p[1]. Does this mean free() do nothing? Once I
allocate memory, I can use later though I have freed it.
