#include <pthread.h>
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <math.h>

int nbthreads = 0;
int iterations = 0;
int run = 1;
int iterations2 = 0;

#define DEFAULTBUFSIZE 1
int globalpipe[2];

int buflen = DEFAULTBUFSIZE;

void exithandler(int s) {
        if (run) {
                run = 0;
                close(globalpipe[0]);
                close(globalpipe[1]);
        }
}

char *fname;


void *thread_code(void *arg) {
        time_t lasttime = time(NULL);
        int jj = (int)arg;
        int localiter = iterations/jj;
        int fd;

        char *buf;

        buf = alloca(buflen);
        if (buf == NULL) {
                printf("Failed to alloca!\n");
                exit(-1);
        }

        do {
                int i;
                time_t newtime;

                for(i=0; i < localiter && run; i++) {
                        int j;
                        double k = 1.0;
                        for(j=0; j < iterations2 && run; j++) {
                                k += j*k;
                                k = (1-k)*(1+k);
                                k = sqrt(k);
                        }
                        if (fd != -1) {
                                if (read(globalpipe[0], buf, buflen)
!= buflen) {
                                        printf("%d, aborted read\n",
jj);
                                }
                        }

                }
                sleep(1);
                newtime = time(NULL);
                printf("%d    delta = %d\n", (int)arg,
newtime-lasttime);
                lasttime = newtime;
        } while (run);
        return NULL;
}


int main(int argc, char **argv) {
        int i;
        pthread_t *mythreads;

        if (argc < 5)
                return -1;

        nbthreads = atoi(argv[1]);
        iterations = atoi(argv[2]);
        iterations2 = atoi(argv[3]);
        buflen = atoi(argv[4]);

        signal(SIGINT, exithandler);

        if (pipe(globalpipe) != 0) {
                return -2;
        }

        mythreads = (pthread_t *)calloc(nbthreads, sizeof(pthread_t));

        for(i=0; i < nbthreads; i++) {
                if (pthread_create(&mythreads[i], NULL, thread_code,
(void *)(i+1)) != 0) {
                        return -5;
                }
                printf("Started %d\n", i);
        }


        void * res;

        char *buf;
        int localbuflen;

        localbuflen = buflen * nbthreads;

        buf = alloca(localbuflen);
        if (buf == NULL) {
                printf("Failed to alloca!\n");
                run = 0;
                exit(-1);
        }

        sleep(3);

        do {
                write(globalpipe[1], buf, localbuflen);
        } while (run);


        for(i=0; i < nbthreads; i++) {
                printf("Waiting %d\n", i);
                pthread_join(mythreads[i], &res);
        }
        return 0;
}