/*									tab:4
 *
 * psample.c - Sample PTHREADS PROGRAM
 *
 */
static char _version_string_[] = "\nVersion:1:psample.c\0\n";

#include <stdio.h>
#include <sys/types.h>
#include <stdlib.h>

#define _REENTRANT 
#include <pthread.h>

#define MAXTHREADS 32
pthread_t tid[MAXTHREADS];
int ready[MAXTHREADS];

volatile int NTHREADS = 0;
volatile int go = 0;

pthread_mutex_t report_mp = PTHREAD_MUTEX_INITIALIZER;
int node = 0;
int reports[MAXTHREADS];


/* Update within critical section for shared data structure */
void report_in (int p)
{
	pthread_mutex_lock(&report_mp);
	reports[node] = p;
	node++;
	pthread_mutex_unlock(&report_mp);	
}

void *start_fun(void *arg)
{
    volatile int barf = 0;
	int i, seed;
	int vp = (int)arg;
	int self = pthread_self();

	while (go == 0) { }			/* Wait to main have everyone created */

	/* spin a random time */
	seed = vp;
	srand(seed);

	for (i = (rand() & 0xffffff); i>0; i--) 	{ barf++;	}
	printf("thread %d looped %d times\n", vp, barf);

	/* Report in through critical section */
	report_in(vp);
}

int main(int argc, char *argv[])
{
  int i, p, create_status;
  pthread_attr_t attr;

  if (argc <= 1) {
	  fprintf(stdout, "usage %s NTHREADS\n", argv[0]);
	  exit(1);
  }
  NTHREADS = atoi(argv[1]);
  if ((NTHREADS < 2) || (NTHREADS > MAXTHREADS))  {
	  fprintf(stdout, "usage %s NTHREADS - where NTHREADS > 1.\n", argv[0]);
	  exit(1);
  }
  printf("%d processors\n", NTHREADS);

  pthread_attr_init(&attr);
  pthread_attr_setscope(&attr, PTHREAD_SCOPE_PROCESS);

  /* Create a collection of worker threads - all at start_fun */
  for (p = 0; p< NTHREADS; p++) {
	  ready[p] = 0;
	  create_status = pthread_create(&tid[p], &attr, start_fun, (void *) p);
	  if (create_status != 0) printf("Error creating threads %d\n",p);
  }

  go = 1;						/* Cheap and dirty barrier */

  /* Wait for them all to finish */
  for (p = 0; p< NTHREADS; p++) {
	  pthread_join(tid[p],NULL);
  }

  /* Print out there reporting order */
  for (i = 0; i< NTHREADS; i++) {
	  printf ("%d->%d.\n", i, reports[i]);  
  }

}