#include "headers.h"
#include <assert.h>
/* error checking left out for legibility */
/* size of thread bevy       */
#define TH_NO  10
/* stuff to pass into thread */
typedef struct thread_arg {
  int id;
  float cost; } arg_t;
/* stuff thread returns      */
typedef struct thread_val {
  int id;
  float cost; } val_t;
/* thing thread does         */
void *entry_point(void *ptr);
/* some verbosity            */
void announce(void);
int main(int argc,  char *argv[]){
  int i;
  pthread_t *thread_ids = (pthread_t *)calloc(TH_NO, sizeof(pthread_t));
  arg_t     *thread_args = (arg_t *)calloc(TH_NO, sizeof(arg_t));
  val_t     **thread_vals = (val_t **)calloc(TH_NO, sizeof(val_t*));
  assert(thread_ids != NULL);
  assert(thread_args != NULL);
  assert(thread_vals != NULL);
  announce();
  for(i = 0; i < TH_NO; i++){
    thread_args[i].id = i;
    thread_args[i].cost = 3.14;
  }
  for(i = 0; i < TH_NO; i++){
    if(pthread_create(&thread_ids[i], NULL, entry_point, &thread_args[i]) != 0){
      fprintf(stderr, "Thread creation failed at i = %d\n", i);
      exit(EXIT_FAILURE);
    }
  }
  for(i = 0; i < TH_NO; i++){
    if(pthread_join(thread_ids[i], (void **)&thread_vals[i]) != 0){
      fprintf(stderr, "Thread joining failed at i = %d\n", i);
      exit(EXIT_FAILURE);
    }
  }
  for(i = 0; i < TH_NO; i++)
    fprintf(stderr,
            "Thread %d produced: %d  %f\n",
            i,
            thread_vals[i]->id,
            thread_vals[i]->cost);
  exit(EXIT_SUCCESS);
}

void *entry_point(void *arg){
  arg_t input;
  val_t *output;
  announce();
  input = *((arg_t *)arg);
  output = (val_t *)malloc(sizeof(val_t));
  assert(output != NULL);
  output->id   = input.id;
  output->cost = input.cost * input.id;
  pthread_exit(output); }

void announce(void){
  fprintf(stderr,
	  "Thread %lu of Process %ld with Parent  %ld\n",
	  (unsigned long int)pthread_self(), (long)getpid(), (long)getppid());
}