Unix 线程同步，使用读写锁
#include <stdlib.h>
#include <pthread.h>
struct job{
struct job * j_next;
struct job *j_prev;
pthread_t j_id;
};
struct queue{
struct job *q_head;
struct job *q_tail;
pthread_rwlock_t q_lock;
};
int queue_init(struct queue *qp)
{
int err;
qp->q_head=NULL;
qp->q_tail=NULL;
err=pthread_relock_init(&qp->q_lock,NULL);
if(err!=0
return(err)
return(0);
}
void job_insert(struct queue *qp, struct job *jp)
{
pthread_rwlock_wrlock(&qp->q_lock);
jp->j_next = qp->q_head;
jp->j_prev = NULL;
if (qp->q_head != NULL)
qp->q_head->j_prev = jp;
else
qp->q_tail = jp; /* list was empty */
qp->q_head = jp;
pthread_rwlock_unlock(&qp->q_lock);
}
void job_append(struct queue *qp, struct job *jp)
{
pthread_rwlock_wrlock(&qp->q_lock);
jp->j_next = NULL;
jp->j_prev = qp->q_tail;
if (qp->q_tail != NULL)
qp->q_tail->j_next = jp;
else
qp->q_head = jp;
qp->q_tail = jp;
pthread_rwlock_unlock(&qp->q_lock);
}
void job_remove(struct queue *qp, struct job *jp)
{
pthread_rwlock_wrlock(&qp->q_lock);
if (jp == qp->q_head) {
qp->q_head = jp->j_next;
if (qp->q_tail == jp)
qp->q_tail = NULL;
} else if (jp == qp->q_tail) {
qp->q_tail = jp->j_prev;
if (qp->q_head == jp)
qp->q_head = NULL;
} else {
jp->j_prev->j_next = jp->j_next;
jp->j_next->j_prev = jp->j_prev;
}
pthread_rwlock_unlock(&qp->q_lock);
}
struct job * job_find(struct queue *qp, pthread_t id)
{
struct job *jp;
if (pthread_rwlock_rdlock(&qp->q_lock) != 0)
return(NULL);
for (jp = qp->q_head; jp != NULL; jp = jp->j_next)
if (pthread_equal(jp->j_id, id))
break;
pthread_rwlock_unlock(&qp->q_lock);
return(jp);
}