我正在尝试用一个新节点更新全局链表。我让列表成为一个指向结构的指针，每次我试图给它分配一个新的成员值时，我都会得到一个总线错误10。我对这件事很感兴趣，所以如果有任何帮助，我们将不胜感激。
代码：
typedef struct alarmItem
{
pthread_t id; //id of the thread to block/unblock
int delay; //initial delay time set by user for this alarm item
int realdelay; //adjusted delay time for this item in the queue
char function[256]; //function for this item to execute once alarm goes off
char args[256]; //arguments to pass into function, sql query or null
time_t calltime; //stores the time that this alarm item was introduced
struct alarmItem* next; //stores the next node in the linked list of alarm items
} alarmItem ;
typedef struct LinkedList
{
alarmItem* head;
} LinkedList;
LinkedList *alarmq; //empty linkedlist of alarm items
void initList()
{
if(alarmq == NULL)
printf("List is null.nn");
else
alarmq->head = NULL;
}
void entry_point(char **arguments)
{
char **args = (char **)arguments;
//create a new alarm item
alarmItem *new;
int d;
sscanf(args[0], "%d", &d);
new->delay = d;
strcpy(new->args, args[3]);
strcpy(new->function, args[4]);
initList();
}
entry_point函数只是通过一个标准的字符串命令列表从主方法调用的。
您需要为new结构分配空间，为此您需要malloc()
void *entry_point(void *data)
{
alarmItem *new;
char **args;
int d;
args = (char **)data;
//create a new alarm item
new = malloc(sizeof(*new));
if (new == NULL)
return NULL; /* may be return something else for error handling */
sscanf(args[0], "%d", &d);
new->delay = d;
strcpy(new->args, args[3]);
strcpy(new->function, args[4]);
initList();
return NULL;
}
您可以看到，我使您的entry_point()函数与pthread_create()一起使用是有效的。
alarmq也是如此，事实上这个条件是
if (alarmq == NULL)
在程序的整个生命周期中都是正确的，我不明白initList()函数应该做什么，但我想它会像一样
void initList()
{
if (alarmq == NULL)
{
alarmq = malloc(sizeof(*alarmq));
if (alarmq != NULL)
alarmq->head = NULL;
}
}
此外，您的链表LinkedList结构并不是真正的链表，您需要在其中包含next成员，而不是alarmItem结构。
to start, replace this:
typedef struct LinkedList
{
alarmItem* head;
} LinkedList;
LinkedList *alarmq; //empty linkedlist of alarm items
void initList()
{
if(alarmq == NULL)
printf("List is null.nn");
else
alarmq->head = NULL;
}
这个：
alarmItem *head = NULL;
这大大简化了过程，从代码中消除了显著的混乱，并且很容易测试要添加的节点是否是第一个（第一个节点几乎总是一种特殊情况）通过：
if( NULL == head )
{ // then, adding first node
...
}
else
{ // else, all other node additions
...
}
这段代码是（我假设）第一个节点是如何添加的
然而，它有几个问题。
--当前代码：
void entry_point(char **arguments)
{
char **args = (char **)arguments;
//create a new alarm item
alarmItem *new;
int d;
sscanf(args[0], "%d", &d);
new->delay = d;
strcpy(new->args, args[3]);
strcpy(new->function, args[4]);
initList();
}
应该更像这样：
（这可以添加任何节点，包括第一个。）
void entry_point(char **args)
{
alarmItem *newNode = NULL;
if( NULL == (newNode = malloc( sizeof(alarmItem) )) )
{ // then, malloc failed
perror( "malloc for alarmItem node failed" );
cleanup(); // new function to free all allocations
exit( EXIT_FAILURE );
}
// implied else, malloc successful
// amongst other things, this sets newNode->next to NULL
memset( newNode, 0x00, sizeof(alarmItem) );
newNode->delay = atoi(args[0]);
strcpy(newNode->args, args[3]);
strcpy(newnode->function, args[4]);
if( NULL == Head )
{ // then, first node to be added
Head = newNode;
}
else
{ // else, append node to end of linked list
alarmItem *tempNode = Head;
alarmItem *currentNode = Head;
while( tempNode->next )
{
currentNode = tempNode;
tempNode = tempNode->next;
} // end while
// when get here, currentNode points to last node in linked list
currentNode->next = newNode;
} // end if
} // end function: entry_point