多线程编程：线程调用函数时传入参数

#include <iostream>
#include <pthread.h>

using namespace std;

#define NUM_THREADS 10

void* say_hello(void* args)
{
    int i = *((int*)args);//对传入的参数进行强制类型转换，由无类型指针变为整形数指针，然后再读取；
    cout << "hello in " << i << endl;
}

int main()
{
    pthread_t tids[NUM_THREADS];
    cout << "hello in main..." << endl;
    for(int i = 0; i < NUM_THREADS; ++i)
    {
        int ret = pthread_create(&tids[i], NULL, say_hello, (void *)&i);//传入的时候必须强制转换为void* 类型，即无类型指针
        cout << "Current pthread id =" << tids[i] << endl;//这里学会使用tids数组打印创建的进程id信息；
        if (ret != 0)
        {
           cout << "pthread_create error: error_code=" << ret << endl;
        }
    }

    pthread_exit(NULL);
}