Probleme avec select

DesSocket=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
	if(DesSocket<0)
		{
			printf("erreur creation socket\n");
			exit(0);
		}

	printf("numero du port : ");
	scanf("%d",&nbport);

struct sockaddr_in addr;
	addr.sin_family=AF_INET;
	addr.sin_port=ntohs(nbport);

struct in_addr addr_en;
	addr_en.s_addr=htonl(INADDR_ANY);

	addr.sin_addr=(addr_en);
FD_ZERO(&rfds);
int Maxsock=0;
int i;
for (i=0;i<nb;i++)
	{
	if(t[i]!=0)
		FD_SET(t[i],&rfds);
	if(Maxsock<t[i])
		Maxsock=t[i];
	}
printf("for passer\n");
	int retval= select(Maxsock+1,&rfds,NULL,NULL,NULL);
		if (retval<0)
			{
			printf("erreur select\n");
			}
printf("select passe\n");

			if(FD_ISSET(DesSocket,&rfds))
			{
				DesSocket1=accept(DesSocket,&addr,&addrlen2);
					if(DesSocket1<0)
					{ printf("erreur accept\n");
					  exit(0);
					}
				nd++;
				t[nd-1]=DesSocket1;
			}
			int k;
			for (k=1;k<nd;k++)
			{
				if(FD_ISSET(t[k],&rfds))
				{
				nb=recv(t[k],&buffer,sizeof(buffer),0);
					if(nb<0)
						{
						printf("reception impossible\n");
						exit(0);
						}
			
				printf("message recu du client : %s \n",buffer);
				}
	
			}