udp server on iOS - ios

Question

I'm trying to send some up sensor data from arduino to my iPhone and i found here (http://www.benripley.com/development/ios/udp-server-on-iphone/) and I run it with some small mods to make it compile on a viewController I display the data and everything works perfectly. But when I leave the view and go back, probably because it tries to start the server again, the app crashes. i tried to move the code to the appDelegate to start the server on launch but the app crashes on launch. even if I try only to start the server on launch and start reading by the time I enter the view and the same thing happens. Any idea?
here is the code:
#include < sys/socket.h >
#include < arpa/inet.h >
#include < errno.h >
#define UDP 17
typedef struct sockaddr_in sockaddr_in;
- (void)startServer {
NSLog(#"UDP Server started...");
sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
struct sockaddr_in sa;
memset(&sa, 0, sizeof(sa));
sa.sin_family = AF_INET;
sa.sin_addr.s_addr = INADDR_ANY;
sa.sin_port = htons(5009);
// bind the socket to our address
if (-1 == bind(sock,(struct sockaddr *)&sa, sizeof(struct sockaddr)))
{
perror("error bind failed");
close(sock);
exit(EXIT_FAILURE);
}
for (;;)
{
recsize = recvfrom(sock,
(void *)buffer,
1024,
0,
(struct sockaddr *)&sa,
&fromlen);
if (recsize < 0)
fprintf(stderr, "%s\n", strerror(errno));
msg = [NSString stringWithFormat:#"%s", buffer];
NSLog(msg);
}
}
and the actual call is this:
[NSThread detachNewThreadSelector:#selector(startServer)
toTarget:self
withObject:nil];