c++多线程参数的传递

#include <iostream>
#include <pthread.h>        //多线程相关操作头文件，可移植众多平台
using namespace std;

struct mypara
{      
    int para1;            //参数1       
    char *para2;        //参数2
    pthread_t wait;
};

void* thread1( void* args )  //本函数演示的是数据的传出
{
    mypara *my = (mypara *)args;
    srand(unsigned(time(0)));
    my->para1 = rand()%100;
    my->para2 = "。";
    cout << "给结构体赋值结束"<< endl;
    return 0;
} 
void* thread2( void* args ) //本函数演示的是数据的传入
{
    mypara *str_in = (mypara *)args;
    cout << "线程2开始运行........................" <<endl;
    pthread_join(str_in->wait,NULL);    //需要等待thread1线程给struct 结构体赋值结束后才能运行
    cout << "线程1产生的随机数是：" << str_in->para1<< " "<< str_in->para2 <<endl;
    return 0;
} 
int main()
{
    pthread_t tid1,tid2; 
    mypara my_para;

    int ret = pthread_create( &tid1, NULL, thread1, (void *)&my_para );    
    //pthread_join(tid1,NULL);
    my_para.wait = tid1;
    pthread_create( &tid2, NULL, thread2, (void *)&my_para );
    system("pause");
    pthread_exit( NULL ); 
}