20  Couche 7 : sockets mode non connecté

• Un exemple de client :

  void *creationAddresseUDP(char *hote,char *service){
  struct addrinfo precisions,*resultat,*origine;
  int statut;
  
  /* Creation de l'adresse de socket */
  memset(&precisions,0,sizeof precisions);
  precisions.ai_family=AF_UNSPEC;
  precisions.ai_socktype=SOCK_DGRAM;
  statut=getaddrinfo(hote,service,&precisions,&origine);
  if(statut<0){ perror("creationAddressUDP.getaddrinfo"); exit(EXIT_FAILURE); }
  struct addrinfo *p;
  for(p=origine,resultat=origine;p!=NULL;p=p->ai_next)
    if(p->ai_family==AF_INET6){ resultat=p; break; }
  
  /* Copie de la structure adresse */
  struct sockaddr_storage *adresse=malloc(sizeof(struct sockaddr_storage));
  if(adresse==NULL){ perror("creationAddressUDP.malloc"); exit(EXIT_FAILURE); }
  memcpy(adresse,resultat->ai_addr,resultat->ai_addrlen);
  
  /* Liberation de la structure d'informations */
  freeaddrinfo(origine);
  
  return adresse;
  }
  
  void messageUDP(int s,void *adresse,unsigned char *message,int taille){
  int nboctets=sendto(s,message,taille,0,(struct sockaddr *)adresse,sizeof(struct sockaddr_storage));
  if(nboctets<0){ perror("messageUDP.sento"); exit(EXIT_FAILURE); }
  }
  

• Programme principal :

  int main(int argc,char *argv[]){
  if(argc!=3){
    fprintf(stderr,"Syntaxe : %s <serveur> <message>\n",argv[0]);
    exit(EXIT_FAILURE);
    }
  char *hote=argv[1];
  char *message=argv[2];
  char *service="4242";
  int s=initialisationSocketUDP("0");
  void *cible=creationAddresseUDP(hote,service);
  int i;
  for(i=0;i<10;i++)
    messageUDP(hote,service,(unsigned char *)&i,sizeof i);
  free(cible);
  close(s);
  return 0;
  }