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Sunday, 22 December 2013

Wild Pointers

Key points on wild pointers:
  • If any of the pointer is uninitialized, then that pointer is called wild pointer.
  • Wild pointers won't refer to any valid memory location.
  • Dereferencing wild pointer would cause segmentation fault.

Consider the following, 
int func() {
int *iptr;
char *cptr;
Here, iptr and cptr are wild pointers.  Because, they are not initialized to NULL.

int func() {
static int *int_ptr;
char *char_ptr;
Here, int_ptr and char_ptr are not wild pointers.  Because, they are static variables.  By default, static variables are initialized to 0.

Below is the example C program on wild pointer.

  #include <stdio.h>
  int main() {
        int *ptr;  // wild pointer
        if (ptr) {
                printf("ptr is not NULL\n");
                *ptr = 10;
                printf("*ptr: %d\n", *ptr);
        return 0;

  Output: (Wild pointer example)
  jp@jp-VirtualBox:~/$ ./a.out
  ptr is not NULL
  Segmentation fault

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