Memory leaks and dangling pointers

If the allocated memory is not released or de-allocated, it causes a memory leak. /* Function with memory leak because programmer forgot to release dynamically allocated memory */ 

#include<stdlib.h> 

void f() 

{ int *ptr =(int*) malloc(10*sizeof(int)); 

/* Do some work */ 

return; /* returns without freeing ptr*/ 

} 

/* Function without memory leak because memory freed by programmer when no longer needed*/ 

#include<stdlib.h> 

void f() 

{ int *ptr =(int*) malloc(10*sizeof(int)); 

/* Do some work */ 

free (ptr): 

return; 

}

A dangling pointer points to a memory location that has already been freed. If we try to access the memory location using the pointer it causes a segmentation fault. 

/* Function without memory leak */ 

#include<stdlib.h> 

void f() 

{ 

int *ptr =(int*) malloc (sizeof(int)) 

*ptr = 10; //valid 

*free (ptr): 

**ptr = 20; // invalid because here ptr is dangling pointer. 

return; 

}

Also Read

1. Static and Dynamic Memory Allocation
2. Memory Allocation for 2D Array
3. Dynamic Memory Allocation
4. Pointer constant and constant pointer
5. Some Pointer Declaration and their Meanings
6. Function and pointers
7. Initializing Pointer to Pointer
8. Pointer to Pointer Multiple Indirection
9. Relationship between Arrays and Pointers
10. Pointer to Array
11. Pointer Arithmetic
12. Types of Pointers
13. Illustrate Basic Pointer Use
14. Using Pointer
15. Intializing Pointer
16. Declaring Pointer
17. Application of Pointers
18. Value Model VS Reference Model
19. What is Pointer