foo.cpp

#include <iostream>
#include <algorithm>
#include <iomanip>
#include <cstring>

#include <stdint.h>
#include <pthread.h>

#include <unistd.h> // sleep()
struct Point {
    int x;
    int y;
};

// a little less insane thread id management since pthread_self returns
// the lwp thread id
int             thread_id      = 0;
pthread_mutex_t thread_id_lock = PTHREAD_MUTEX_INITIALIZER;

int thread_id_next(void) {
    int ret;
    pthread_mutex_lock(&thread_id_lock);
    ret = ++thread_id;
    pthread_mutex_unlock(&thread_id_lock);
    return ret;
}

void *PrintXY(void *data) {
    Point    *point = reinterpret_cast<Point*>(data);
    pthread_t self  = pthread_self();

    sleep(point->x);

    std::cout << "thread id: " << thread_id_next() << "\n";
    std::cout << "lwp id:    " << std::hex         << *reinterpret_cast<uint64_t*>(&self) << "\n";
    std::cout << point->x      << "\n";
    std::cout << point->y      << std::endl;

    return reinterpret_cast<void*>(new int(27));
}

int main(int argc, char **argv, char **envp) {
    // threads
    pthread_t  t1;
    pthread_t  t2;
    // points
    Point      p1 = { 1, 2 };
    Point      p2 = { 3, 4 };
    // controls
    int        c1;
    int        c2;
    // returns
    int       *r1 = 0;
    int       *r2 = 0;

    if ((c1 = pthread_create(&t1, NULL, &PrintXY, (void*)&p1)))
        std::cerr << "error = " << c1 << std::endl;

    if ((c2 = pthread_create(&t2, NULL, &PrintXY, (void*)&p2)))
        std::cerr << "error = " << c2 << std::endl;

    // join will wait
    pthread_join(t1, reinterpret_cast<void **>(&r1));
    pthread_join(t2, reinterpret_cast<void **>(&r2));

    std::cout << "the status of thread 1: " << std::dec << *r1 << "\n";
    std::cout << "the status of thread 2: " << std::dec << *r2 << std::endl;

    // free the resources
    delete r1;
    delete r2;
}