C Debugging Note

==Updating==

---

Memory leak issues:

• Assigning NULL to a dynamically allocated memory block. Will not be freed later.

    char ** arg = calloc(1, sizeof(char *));
    arg[0] = calloc(10, sizeof(char));
    arg[0] = NULL;
    free(arg); // MEMORY LEAK!

• Rewriting to a freed memory block.

  In some weird cases, the programme will run smoothly for several steps (writing) and then throw a segmentation fault error.

• Always draw a diagram for the changes you made.