Socket select don't work - c

Question

i don't know why the select function don't return any result.
I put the server in execution with this command:
./server 5555
and i try to send any character from another terminal, using:
nc 127.0.0.1 5555
and
any string to send
This is the source code of the server.c
#include <stdlib.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <errno.h>
#define MAXSIZE 1000
int main(int argc, char **argv) {
int socketfd, connectedfd, maxfd;
int ris, i, len, ris1, sent, opt;
struct sockaddr_in serverS, clientS;
short int localServerPort;
fd_set rdfs, wrfs;
char buffer[MAXSIZE];
if (argc != 2) {
printf("necessario un parametro PORTNUMBER");
exit(1);
} else {
localServerPort = atoi(argv[1]);
}
socketfd = socket(AF_INET, SOCK_STREAM, 0);
if (socketfd < 0) {
printf("socket() error\n");
exit(1);
}
opt = 1;
ris = setsockopt(socketfd, SOL_SOCKET, SO_REUSEADDR, (char *)&opt, sizeof(opt));
if (ris < 0) {
printf ("setsockopt() SO_REUSEADDR failed, Err: %d \"%s\"\n", errno,strerror(errno));
exit(1);
}
memset(&serverS, 0, sizeof(serverS));
serverS.sin_family = AF_INET;
serverS.sin_addr.s_addr = htonl(INADDR_ANY);
serverS.sin_port = htons(localServerPort);
ris = bind(socketfd, (struct sockaddr*)&serverS, sizeof(serverS));
if (ris < 0) {
printf("bind() error");
exit(1);
}
ris = listen(socketfd, 10);
if (ris < 0) {
printf("listen() error");
exit(1);
}
len = sizeof(clientS);
connectedfd = accept(socketfd, (struct sockaddr*)&clientS, &len);
if (connectedfd < 0) {
printf("accept() error");
exit(1);
} else {
printf("Connesso con: %s:%d - descrittore: %d\n", inet_ntoa(clientS.sin_addr), ntohs(clientS.sin_port), connectedfd);
}
fd_set tempset;
FD_ZERO(&rdfs);
//FD_ZERO(&wrfs);
FD_SET(connectedfd, &rdfs);
maxfd = connectedfd + 1;
while (1) {
printf("Select...\n");
ris = select(connectedfd, &rdfs, NULL, NULL, NULL);
printf("test\n");
if (ris == 0) {
printf("select() timeout error\n");
} else if (ris < 0 && errno != EINTR) {
printf("select() error\n");
} else if (ris > 0) {
printf("test ris > 0\n");
for (i = 0; i < maxfd+1; i++) {
if (FD_ISSET(i, &rdfs)) {
do {
ris = recv(i, buffer, MAXSIZE, 0);
} while (ris == -1 && errno == EINTR);
if (ris > 0) {
buffer[ris] = 0;
printf("Echoing: %s\n", buffer);
sent = 0;
do {
ris1 = send(i, buffer+sent, ris-sent, MSG_NOSIGNAL);
if (ris1 > 0)
sent += ris1;
else if (ris1 < 0 && errno != EINTR);
break;
} while (ris > sent);
}
else if (ris == 0) {
close(i);
FD_CLR(i, &rdfs);
}
else {
printf("Error in recv(): %s\n", strerror(errno));
}
}
}
}
}
return(0);
}
Why the execution remain locked at "Select...\n"?
Thanks to all!

Answer 1

From http://linux.die.net/man/2/select, the first param passed should be the highest-numbered file descriptor in any of the three sets (read/write/exception), plus 1. I would try the following:
ris = select(connectedfd+1, &rdfs, NULL, NULL, NULL);