看unix高级环境编程11-9实在看不懂代码是神魔意思?
本帖最后由 senlin8350 于 2012-09-08 10:49 编辑#include<pthread.h>
struct msg{
struct msg *m_next;
};
struct msg *workq;
pthread_cond_t qready = PTHREAD_COND_INITIALIZER;
pthread_mutex_t qlock = PTHREAD_MUTEX_INITIALIZER;
void process_msg(void)
{
structmsg *mp;
for(;; ){
pthread_mutex_lock (&qlock);
while(work == NULL)
pthread_cond_wait(&qready, &qlock )
mp = workq;
workq = mp->next;
pthread_mutex_unlock(&qlock);
}
}
void
enqueue_msg(structmsg *mp)
{
pthread_mutex_lock(&qlock);
mp->m_next = workq;
workq = mp;
pthread_mutex_unlock(&qlock);
pthread_cond_signal(&qready);
} workq:指向当前消息结点的指针;
第二个函数中的mp指向新消息结点;workq = mp;//将新消息放入workq全局变量中,并通知process_msg;
process_msg收到信号,并重新获得锁(隐式)后,将workq里的消息提取放入mp中( mp = workq;);再重设workq( workq = mp->next;);释放锁(显式);开始对mq处理。 是从队列头节点,然后将队列头节点调整为刚才头结点的下一个节点。
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