释放strdup分配的内存

Question

如何释放strdup分配的内存？ 我尝试在此函数结束时使用free（linepos），但这导致我的程序失败。我在这个函数之外没有linepos，所以我无法在其他任何地方释放它。提前谢谢。

void putinqueue (queue *the_queue, FILE *input, char *filename) {
   char buffer[1024];
   for (int linenr = 1; ; ++linenr) {
      char *linepos = fgets (buffer, sizeof buffer, input);
      if (linepos == NULL) break;
      linepos = strchr (buffer, '\n');
      if (linepos == NULL) {
         fflush (NULL);
         fprintf (stderr, "%s: %s[%d]: unterminated line\n",
                  execname, filename, linenr);
         fflush (NULL);
         exit_status = EXIT_FAILURE;
      }else {
         *linepos = '\0';
      }
      linepos = strdup (buffer);
      assert (linepos != NULL);
      insert_queue (the_queue, linepos);
   }
}

编辑：这是其他功能。抱歉，复制并粘贴旧来源。这是新的。

void insert_queue (queue *this, queue_item_t item) {
   //Inserts a new item at the end of queue.
   queue_node *temp = malloc(sizeof (struct queue_node));
   temp->item = item;
   temp->link = NULL;

   if (isempty_queue(this)) this->front = temp; 
   else this->rear->link = temp;
   this->rear = temp;
}

queue_item_t remove_queue (queue *this) {
   //This removes the first item from queue.
   assert (! isempty_queue (this));
   //Creates temp, and rVal and initializes them.
   queue_node *temp = this->front;
   queue_item_t rVal = temp->item;

   //Moves on to the next one.
   this->front = this->front->link;
   if (this->front == NULL) this->rear = NULL;
   //Free the unlinked node.
   free(temp);
   temp = NULL;
   return rVal;
}