xcode - C linked list: Segmentation fault on Windows, works on Mac -

i'm trying go through linked list in c.

a list item defined as

struct list_element {   struct list_element *next;   int value; }; 

the list head defined as

struct list_head {   struct list_element *front;   struct list_element *end; }; 

and i'm trying print items

void printlist(struct list_head* head) {     if(head == null|| head->front == null) {         printf("list empty \n");         return 0;     }      struct list_element* elm = head-> front;     int numberofelements = 0;      while(elm != null) {         printf("%i", elm -> value);         printf(" ");         elm = elm -> next;     }     printf("\n"); } 

this works perfect on mac in xcode , on https://ideone.com, on windows , http://codepad.org results in "segmentation fault". seems

while(elm != null) {     printf("%i", elm -> value);     printf(" ");     elm = elm -> next; } 

causes issues. seems elm doesn't point null last item, though should.

i'm adding items

struct list_element* list_push(struct list_head* head) {      //list head null     if(!head) {         return null;     }      //initialize list element      struct list_element* elm = malloc(sizeof(struct list_element));      if(elm == null) {         //couldn't alloc memory         return null;     }      if(head->front) {         head->front = elm;         head->end = elm;     } else {         //list head not null, set next elm point current elm         elm -> next = head -> front;         head->front = elm;      }      return elm; } 

and i'm confused why same code work in places not in others. (it works on ideone , xcode, doesn't work on codepad , code::blocks on windows same code)

example on ideone example on codepad

you have initialize ele->next null first element of list, otherwise access uninitialized memory in elm = elm->next last element of list. apart have change if(head->front) if ( head->front == null ). adapt code this:

struct list_element* list_push(struct list_head* head) {      if ( head == null )         return null;      struct list_element* elm = malloc(sizeof(struct list_element));     if ( elm == null)         return null;      if ( head->front == null)  // <--------------     {         elm->next = null;     // <---------------         head->front = elm;         head->end = elm;     }     else     {             elm->next   = head->front;         head->front = elm;     }     return elm; } 

make sure initialized head->front head->end null.