Question

Code is as follows:

/* set.h */
struct setElement{
  char *element;
  setElement *next;
};

typedef struct setElement *Set;  //Set is now the equivalent of setElement*

Set a;    

setInit(&a);

/* setInit function declaration @ setInit.c */

int setInit(Set *a){
  (*a)->element = "asdf";  //results in a seg fault
}

Trying to malloc ‘a’ works, but if I try to access any member within the set ‘a’ doesn’t work. I understand I’m passing a reference of the set from the main() function to setInit, so I believe the pointer contained within setInit is addressing the memory allocated by ‘Set a’ in the main() function, so a malloc wouldn’t be required…

Iunno. Help is appreciated 🙂

Answer 1

The problem is that you have not allocated the setElement you are trying to assign to. In the main part of the code you are creating a Set, which is just a pointer to a setElement. This pointer is never set to point to anything sensible. I.e. you need something like

Set a = malloc(sizeof(setElement));