用二级指针删除单链表的一个节点

一般删除方法：

node *remove_if(node *head, remove_fn rm)
{
    node *cur = head, *prev = NULL;
    while(cur)
    {
        node *next = cur->next;
        if( rm(cur) )
        {
            if(prev)
                prev->next = next;
            else
                head = next;
            free(cur);
        }
        else
            prev = cur;
        cur = next;
    }
    return head;
}

二级指针删除方法：

node *remove_if(node **phead, remove_fn rm)
{
    for( node **cur = phead; *cur; )
    {
        node *entry = *cur;
        if( rm(entry) )
        {
            *cur = entry->next;
            free(entry);
        }
        else
            cur = &entry->next;
    }
    return *head;
}

一个最简单的链表应该是下面的结构：