#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <errno.h>
#include <sys/ipc.h>
#include <semaphore.h>
int lock_var;
time_t end_time;
sem_t sem1,sem2;
void pthread1(void *arg);
void pthread2(void *arg);
int main(int argc, char *argv[])
{
pthread_t id1,id2;
pthread_t mon_th_id;
int ret;
end_time = time(NULL)+30;
ret=sem_init(&sem1,0,1);
ret=sem_init(&sem2,0,0);
if(ret!=0)
{
perror("sem_init");
}
ret=pthread_create(&id1,NULL,(void *)pthread1, NULL);
if(ret!=0)
perror("pthread cread1");
ret=pthread_create(&id2,NULL,(void *)pthread2, NULL);
if(ret!=0)
perror("pthread cread2");
pthread_join(id1,NULL);
pthread_join(id2,NULL);
exit(0);
}
void pthread1(void *arg)
{
int i;
while(time(NULL) < end_time){
sem_wait(&sem2);
for(i=0;i<2;i++){
sleep(1);
lock_var++;
printf("lock_var=%d\n",lock_var);
}
printf("pthread1:lock_var=%d\n",lock_var);
sem_post(&sem1);
sleep(1);
}
}
void pthread2(void *arg)
{
int nolock=0;
int ret;
while(time(NULL) < end_time){
sem_wait(&sem1);
printf("pthread2:pthread1 got lock;lock_var=%d\n",lock_var);
sem_post(&sem2);
sleep(3);
}
}
