Pthread CS 162 B Lab 7

pthread.cpp

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <pthread.h>
#include <unistd.h>

using namespace std;
typedef void* object;

int *arr;
object pass_an_int(object);

int main(int argc, char *argv[]) {

	if (argc == 1) {
		printf("Please pass an argument containing the thread ID.\n");
		return 255;
	}

	int n = argc - 1;

	pthread_t *threads = new pthread_t[n];
	arr = new int[n];

	// create threads
	for (int i = 0; i < n; ++i) {
		arr[i] = atoi(argv[i + 1]);
		int error = pthread_create(threads + i, NULL, pass_an_int, reinterpret_cast<object>(i));
		if (error) {
			printf("Thread (%d) returned error code (%d)!!!!", i, error);
			return 255;
		}
	}

	// join threads
	for (int i = 0; i < n; ++i) {
		pthread_join(threads[i], NULL);
	}

	// clean up
	delete[] threads, arr;
	return 0;

}

object pass_an_int(object value) {
	int X = *(int*) &value;
	int old = arr[X];
	arr[X] *= (X % 2 ? -1 : old * old);
	printf("%d(old) has been replaced with %d(new)\n", old, arr[X]);
}