Question

我有一个帖子，我希望传递3个参数。所以，我把它们放在一个结构中，如下所示：

struct arg
{
time_t  time1;
float name1;
time_t quantum1;
};

我通过以下方式传递了参数：

 arg arg1;
 arg1.time1=(time_t)(int)job.peek(); //job.peek() was 3
 cout<<"job time is "<<arg1.time1<<endl; //this output 3

 arg1.name1=(float)(int)job.returnname(NULL); //job.returnname() was 1
 cout<<"job name is "<<arg1.name1<<endl;// this output 1

 arg1.quantum1=quantum; //quantum was 7
 cout<<"quantum is "<<arg1.quantum1<<endl;//this output 7

 pthread_create(&thread1, NULL, func3, (void*)(&arg1));

但是当我在线程本身的开头检查这些值时，它们就被更改了。

 void* timer(void *argum)
 {
 arg *arg1= (arg*)argum;
 cout<<"PROCESS "<<arg1->name1<<" HAS ENTERED THE TIMER"<<endl; //this output arg1->name1 as 1.4013e-45
 cout<<"Time remaining for process is "<<arg1->time1<<endl; //this output arg1->time1 as -1218381144
 cout<<"quantum is "<<arg1->quantum1<<endl; //this output arg1->quantum1 as 5
 }

有人可以告诉我为什么会这样吗？在此先感谢!!

Answer 1

您不应该从函数中传递本地对象的地址（即在堆栈上创建）。您应该使用malloc / new分配它。

Answer 2

问题是您在堆栈上分配了arg1，并且该内存超出了范围并在线程开始执行之前重用。使用malloc或new在堆上分配arg对象，并且在完成后不要忘记取消分配它，通常是在您创建的线程中。

将参数传递给线程

2 个答案: