Doubly Linked List Segmentation Fault
So i've never really worked with doubly linked lists in terms of coding, and I didn't do great with singly linked lists either. I have it all coded out but it's giving me a segmentation fault when I run it. I have looked over all my code and have no idea whats wrong, in add event i malloc one node of space then find where to add it and add it. i only add 1 per call to add event so that shouldnt be an issue. is there an initial part im missing when you first start the list?
[note all of the variables and definitions you see that aren't in the code are in one of the 2 external files if u need more info from them to help let me know.
osdefs.h
Code:
struct event_list
{
/** Type of event. */
event_type event;
/** User or device causing the event. */
int agent;
/** Time event occurs. */
struct time_type time;
/** Next event node in list. */
struct event_list* prev;
/** Previous event node in list. */
struct event_list* next;
};
typedef struct event_list event_list;
externs.h
Code:
extern event_list* Event_List; ///< Pointer to head of event list
obj1.c
Code:
void Add_Event( int event, int agent, struct time_type* time )
{
//Header points to the head of the list.
event_list* header = Event_List;
event_list* temp;
temp = malloc(sizeof(event_list));
temp->event = event;
temp->agent = agent;
temp->time.nanosec = time->nanosec;
temp->time.seconds = time->seconds;
temp->next = NULL;
temp->prev = NULL;
if(Event_List==NULL)
{
// header = temp;
Event_List = temp;
return;
}
//While header is not the last node in the list.
while(header!=NULL){
//First compare the temporary nodes seconds to the header's seconds. If they are the same:
//compare nanoseconds of each node, if we enter the loop then temp precedes header.
if(temp->time.seconds < header->time.seconds || (temp->time.seconds == header->time.seconds && temp->time.nanosec <= header->time.nanosec))
{
//Make temp the new head of the list.
//temp->next now pointts to header.
if(header->prev = NULL)
{
header->prev = temp;
temp->next = header;
temp->prev = NULL;
Event_List = temp;
header = NULL;
}
else
{
//Insert into the middle of the list.
header->prev->next = temp;
temp->prev = header->prev;
header->prev = temp;
temp->next = header;
header = NULL;
}
}//end outer if
//Inserting at the end of the list temp->previous is set as header.
else if(header->next == NULL)
{
header->next = temp;
temp->prev = header;
temp->next = NULL;
header = NULL;
}
//Advance the header to the next node in the list.
else
header=header->next;
}//end while
}
