Hiroshi Yamaguchi / Mbed 2 deprecated SimpleSocketExamples 1.0

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Dependencies:   EthernetNetIf SimpleSocket 1.0 mbed

ntpclient.cpp

Committer:
yamaguch
Date:
2011-10-26
Revision:
32:00114e36de90
Child:
33:39d9cdf99de8

File content as of revision 32:00114e36de90:

#include "EthernetNetIf.h"
#include "SimpleSocket.h"

void ntpclient() {
    char *NTP_SERVER = "pool.ntp.org";
    
    printf("ntp client - %s\n", NTP_SERVER);

    while (true) {
        DatagramSocket datagram;
        char buf[48] = {0x23};// 00100011 LI(0), Version(4), Mode(3: Client)
        datagram.write(buf, sizeof(buf));
        datagram.send(NTP_SERVER, 123);
        
        if (datagram.receive() > 0) {
            if (datagram.read(buf, sizeof(buf))) {
                unsigned long seconds = 0;
                for (int i = 40; i <= 43; i++)
                    seconds = (seconds << 8) | buf[i];
                seconds -= 2208988800ULL;               
                set_time((time_t) seconds);
                
                char buf[16];
                time_t jstime = time(NULL) + 9 * 3600;
                strftime(buf, sizeof(buf), "%m/%d %X", localtime(&jstime));
                printf("Time: %s\n", buf);
                break;
            }
        }
    }
}