Diff: examples/ntpclient.cpp

Revision:

0:6dc3cfd058c6

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/ntpclient.cpp	Mon Feb 04 09:29:18 2013 +0000
@@ -0,0 +1,31 @@
+#include "SimpleSocket.h"
+
+void ntpclient() {
+    char *NTP_SERVER = "pool.ntp.org";
+    printf("ntp server = %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);
+        
+        //datagram.setTimeout(5.0);
+        if (datagram.receive() > 0) {
+            if (datagram.read(buf, sizeof(buf)) > 0) {
+                unsigned long seconds = 0;
+                for (int i = 40; i <= 43; i++)
+                    seconds = (seconds << 8) | buf[i];
+                set_time(time_t(seconds - 2208988800ULL));
+                char timestamp[16];
+                time_t jstime = time(NULL) + 9 * 3600;
+                strftime(timestamp, sizeof(timestamp), "%m/%d %X", localtime(&jstime));
+                printf("Time: %s\n", timestamp);
+                break;
+            }
+        } else {
+            printf("no answer\n");
+            wait(1.0);
+        }
+    }
+}
\ No newline at end of file