Ubuntu下多线程简单的线程锁抢门票问题

  1 #include<stdio.h>
  2 #include<pthread.h>
  3 #include<stdlib.h>
  4 #include<string.h>
  5 #include<sched.h>
  6 #include<unistd.h>
  7 #define NUMBER 10   //总票数
  8 static int ticket=NUMBER;
  9 static int ticket1;//标志，1 有票 0 无票
 10 static pthread_mutex_t mut=PTHREAD_MUTEX_INITIALIZER;
 11 static void *send(void *arg);
 12 int main(void)
 13 {
 14     pthread_t tid[4];
 15     int err;
 16     for(int i=1;i<5;i++){
 17         err=pthread_create(tid+i-1,NULL,send,(void *)i);
 18         if(err){
 19             fprintf(stderr,"pthread_create() %s \n",strerror(err));
 20             exit(1);
 21         }
 22     }
 23     //for(int i=0;i<5;i++)
 24     //  pthread_detach(tid[0]);
 25     pthread_mutex_lock(&mut);
 26     while(ticket){
 27         ticket1=1;
 28         pthread_mutex_unlock(&mut);
 29         sched_yield();
 30         pthread_mutex_lock(&mut);
 31         ticket--;
 32     }
 33     pthread_mutex_unlock(&mut);
 34 
 35 
 36     for(int i=0;i<4;i++){
 37         pthread_join(tid[i],NULL);
 38     }
 39 
 40     exit(0);
 41 
 42 }
 43 static void *send(void *arg){
 44     int a=(int)arg;//接收窗口编号
 45     
 46     pthread_mutex_lock(&mut);
 47     while(ticket){
 48         while(!ticket1){
 49             pthread_mutex_unlock(&mut);
 50             sched_yield(); //这步不需要，本窗口卖出可以继续卖                                                                                                                                                                                                                                               
 51             pthread_mutex_lock(&mut);
 52             if(ticket==0)
 53                 goto ER;
 54         }
 55         ticket1=0;
 56         sleep(1);
 57         printf("窗口[%d]卖出了No.[%d]演唱会门票\n",a,NUMBER-ticket+1);
 58     //  pthread_mutex_unlock(&mut);
 59         
 60     }
 61     pthread_mutex_unlock(&mut);
 62     pthread_exit((void *)0);
 63 ER: 
 64     pthread_mutex_unlock(&mut);
 65     pthread_exit((void *)0);
 66 }   

zj@zj-pc:~/6.dir/3-29.c/ticket$ gcc ticket.c -pthread
ticket.c: In function ‘main’:
ticket.c:17:40: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
   err=pthread_create(tid+i-1,NULL,send,(void *)i);
                                        ^
ticket.c: In function ‘send’:
ticket.c:44:8: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  int a=(int)arg;

zj@zj-pc:~/6.dir/3-29.c/ticket$ ./a.out 
窗口[2]卖出了No.[1]演唱会门票
窗口[1]卖出了No.[2]演唱会门票
窗口[1]卖出了No.[3]演唱会门票
窗口[4]卖出了No.[4]演唱会门票
窗口[4]卖出了No.[5]演唱会门票
窗口[4]卖出了No.[6]演唱会门票
窗口[4]卖出了No.[7]演唱会门票
窗口[1]卖出了No.[8]演唱会门票
窗口[1]卖出了No.[9]演唱会门票
窗口[2]卖出了No.[10]演唱会门票