多读多写下，先进后出队列，可以不加锁，下面是实现代码 lifo.h
#include "cas.h"
#include <stddef.h>struct lifo_node
{
volatile struct lifo_node *next;
};struct lifo
{
void init() {
top = NULL;
cnt=0;
}void push(lifo_node *node) {
struct lifo old_val, new_val;
do {
old_val = *this;
node->next = old_val.top;
new_val.top = node;
new_val.cnt = old_val.cnt;
}while(!CAS2(this, old_val, new_val));
}
lifo_node * pop() {
struct lifo_node *node;
struct lifo old_val, new_val;
do {
old_val = *this;
node = old_val.top;
new_val.top = old_val.top;
new_val.cnt = old_val.cnt+1;
}while(!CAS2((this), old_val, new_val));
return node;
}struct lifo_node * volatile top;
volatile unsigned int cnt;
};