山东大学操作系统实验六报告死锁问题

sem_id = id; }

Sema::~Sema(){ }

int Sema::down() {

struct sembuf buf;

buf.sem_op = -1;

buf.sem_num = 0;

buf.sem_flg = SEM_UNDO;

if((semop(sem_id,&buf,1)) <0) {

perror(\

exit(EXIT_FAILURE); }

return EXIT_SUCCESS; }

int Sema::up() {

Sem_uns arg;

struct sembuf buf;

buf.sem_op = 1;

buf.sem_num = 0;

buf.sem_flg = SEM_UNDO;

if((semop(sem_id,&buf,1)) <0) {

perror(\

exit(EXIT_FAILURE); }

return EXIT_SUCCESS; }

Lock::Lock(Sema * s) { sema = s;

}

Lock::~Lock(){ } //上锁

void Lock::close_lock() {

sema->down(); } //开锁

void Lock::open_lock() {

sema->up();