Avertissement: fonte/à partir de pointeur à partir de/à l'entier de taille différente

J'apprends Pthreads. Mon code s'exécute comme je le veux, je suis capable de l'utiliser. Mais cela me donne un avertissement sur la compilation.

Je compile en utilisant:

gcc test.c -o test -pthread

Avec GCC 4.8.1. Et je reçois l'avertissement

test.c: In function ‘main’:
test.c:39:46: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
     pthread_create(&(tid[i]), &attr, runner, (void *) i);
                                              ^
test.c: In function ‘runner’:
test.c:54:22: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
   int threadnumber = (int) param;
                      ^

Cette erreur vient pour le code suivant:

#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>

#define MAX_THREADS 10

int sum; /* this data is shared by the thread(s) */
void *runner(void * param);

int main(int argc, char *argv[])
{
  int num_threads, i;
  pthread_t tid[MAX_THREADS];     /* the thread identifiers  */
  pthread_attr_t attr; /* set of thread attributes */

  if (argc != 2) {
    fprintf(stderr, "usage:  test <integer value>n");
    exit(EXIT_FAILURE);
  }

  if (atoi(argv[1]) <= 0) {
    fprintf(stderr,"%d must be > 0n", atoi(argv[1]));
    exit(EXIT_FAILURE);
  }

  if (atoi(argv[1]) > MAX_THREADS) {
    fprintf(stderr,"%d must be <= %dn", atoi(argv[1]), MAX_THREADS);
    exit(EXIT_FAILURE);
  }

  num_threads = atoi(argv[1]);
  printf("The number of threads is %dn", num_threads);

  /* get the default attributes */
  pthread_attr_init(&attr);

  /* create the threads */
  for (i=0; i<num_threads; i++) {
    pthread_create(&(tid[i]), &attr, runner, (void *) i);
    printf("Creating thread number %d, tid=%lu n", i, tid[i]);
  }

  /* now wait for the threads to exit */
  for (i=0; i<num_threads; i++) {
    pthread_join(tid[i],NULL);
  }
  return 0;
}

/* The thread will begin control in this function */
void *runner(void * param)
{
  int i;
  int threadnumber = (int) param;
  for (i=0; i<1000; i++) printf("Thread number=%d, i=%dn", threadnumber, i);
  pthread_exit(0);
}

Comment puis-je corriger cet avertissement?