(Objective-C) Get Current Date/Time from NIST Time Server

Demonstrates using Chilkat Socket to connect to an NIST time server and (using the old Time Protocol (RFC 868)), will read the current GMT time.

Note: This is not necessarily the very best means for getting the current date/time. The most commonly used time protocol is the Network Time Protocol (RFC-1305).

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#import <CkoSocket.h>
#import <CkoDateTime.h>

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

CkoSocket *socket = [[CkoSocket alloc] init];

// Connect to an NIST time server and read the current date/time
int maxWaitMs = 4000;
BOOL useTls = NO;
BOOL success = [socket Connect: @"time-c.nist.gov" port: [NSNumber numberWithInt: 37] ssl: useTls maxWaitMs: [NSNumber numberWithInt: maxWaitMs]];
if (success != YES) {
    NSLog(@"%@",socket.LastErrorText);
    return;
}

// The time server will send a big-endian 32-bit integer representing
// the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
// The ReceiveInt32 method will receive a 4-byte integer, but returns
// YES or NO to indicate success.  If successful, the integer
// is obtained via the ReceivedInt property.
BOOL bigEndian = YES;
success = [socket ReceiveInt32: bigEndian];
if (success != YES) {
    NSLog(@"%@",socket.LastErrorText);
    return;
}

CkoDateTime *dt = [[CkoDateTime alloc] init];
[dt SetFromNtpTime: socket.ReceivedInt];

// Show the current local date/time
BOOL bLocalTime = YES;
NSLog(@"%@%@",@"Current local date/time: ",[dt GetAsRfc822: bLocalTime]);

maxWaitMs = 10;
[socket Close: [NSNumber numberWithInt: maxWaitMs]];