C++ Многопоточность

#include <pthread.h>
#include <iostream>
using namespace std;
#include <stdlib.h>
#include <unistd.h>
 
void *run(void *param);
 
int main(int argc, char *argv[])
{
    //First we take the input of argv[1] and convert it to an integer type.
    //Also iCounter will be our counter for amount of threads.
    int iAmtOfThrds = atoi(argv[1]), iCounter;
 
    pthread_t tid[100]; //Thread id array for 'x' amount of threads.
    pthread_attr_t attr; //Thread attributes
    pthread_attr_init(&attr); //Initial thread attributes
 
    //Start for...loop to create 'x' amount of threads
    //Then pass it to the run() function.
    for(iCounter = 0; iCounter < iAmtOfThrds; iCounter++)
    pthread_create(&tid[iCounter], &attr, run, argv[1]); //Create a new thread multiple times
 
    //Start for...loop to wait for each thread to finish
    for(iCounter = 0; iCounter < iAmtOfThrds; iCounter++)
    pthread_join(tid[iCounter], NULL); //Wait for the new thread to finish
}
     
void *run(void *param)
{
    cout << "Starting New Thread.\n";
    sleep(10);//System Call to let the thread sleep for 10 seconds.
    cout << "Thread finished, exiting function.\n";
    pthread_exit(0);//Exits thread.
}