File content as of revision 0:b90f9dc5cf9c:

#include "mbed.h"
#include "EthernetInterface.h"
 
// Network interface
EthernetInterface net;

// Time protocol implementation : Address: time.nist.gov UDPPort: 37  

typedef struct {
    uint32_t secs;         // Transmit Time-stamp seconds.
}ntp_packet;

int main() {
    // Bring up the ethernet interface
    printf("UDP Socket example\n");
    if(0 != net.connect()) {
        printf("Error connecting\n");
        return -1;
    }

    // Show the network address
    const char *ip = net.get_ip_address();
    printf("IP address is: %s\n", ip ? ip : "No IP");
        
    UDPSocket sock(&net);
    SocketAddress sockAddr;

    char out_buffer[] = "time";
    if(0 > sock.sendto("time.nist.gov", 37, out_buffer, sizeof(out_buffer))) {
        printf("Error sending data\n");
        return -1;
    }
    
    ntp_packet in_data;
    int n = sock.recvfrom(&sockAddr, &in_data, sizeof(ntp_packet));
    in_data.secs = ntohl( in_data.secs ) - 2208988800;    // 1900-1970
    printf("Time Received %lu seconds since 1/01/1900 00:00 GMT\n", (uint32_t)in_data.secs);
    printf("Time = %s", ctime(( const time_t* )&in_data.secs));
    
    printf("Time Server Address: %s Port: %d\n\r", sockAddr.get_ip_address(), sockAddr.get_port());
    
    // Close the socket and bring down the network interface
    sock.close();
    net.disconnect();
    return 0;
}