CODEWITHSUNDEEP
iosswift
TimSim
TimSim

Reputation: 4036

Getting system uptime in iOS/Swift

Is there a way to get system uptime in iOS (using Swift)? What I need is to measure time without having to worry about the user changing the time. In Android there's a elapsedCurrentTimeMillis() that returns the number of milliseconds since boot, but now I need something like that for iOS. There's an accepted answer here Getting iOS system uptime, that doesn't pause when asleep but that's for Objective C and I need it for Swift and I don't know how to convert it.

Upvotes: 6

Views: 10743

Answers (4)

Richard Poutier
Richard Poutier

Reputation: 217

Updated for Swift 5 and straight from ADF post here:

func bootTime() -> Date? {  
    var tv = timeval()  
    var tvSize = MemoryLayout<timeval>.size  
    let err = sysctlbyname("kern.boottime", &tv, &tvSize, nil, 0);  
    guard err == 0, tvSize == MemoryLayout<timeval>.size else {  
        return nil  
    }  
    return Date(timeIntervalSince1970: Double(tv.tv_sec) + Double(tv.tv_usec) / 1_000_000.0)  
}

"Be aware that this time will change if the system clock changes, that is, the value is the boot time relative to the current system clock."

Upvotes: 7

Anthony Kong
Anthony Kong

Reputation: 40664

This is a solution in Swift 4.

 var boottime = timeval()
 var size = MemoryLayout<timeval>.stride
 sysctlbyname("kern.boottime", &boottime, &size, nil, 0)

Upvotes: 6

Donghua Li
Donghua Li

Reputation: 451

As you ask for a pure-Swift solution, I converted the ObjC code from the answer you mentioned Getting iOS system uptime, that doesn't pause when asleep.

func uptime() -> time_t {
    var boottime = timeval()
    var mib: [Int32] = [CTL_KERN, KERN_BOOTTIME]
    var size = strideof(timeval)

    var now = time_t()
    var uptime: time_t = -1

    time(&now)
    if (sysctl(&mib, 2, &boottime, &size, nil, 0) != -1 && boottime.tv_sec != 0) {
        uptime = now - boottime.tv_sec
    }
    return uptime
}

// print(uptime())

To make it a bit prettier, we can use sysctlbyname instead of sysctl:

// var mib: [Int32] = [CTL_KERN, KERN_BOOTTIME]
sysctlbyname("kern.boottime", &boottime, &size, nil, 0)

Upvotes: 16

Donghua Li
Donghua Li

Reputation: 451

You can call ObjC code from Swift:

print(SystemUtil().uptime());

Write a ObjC class like the accepted answer you mentioned: Getting iOS system uptime, that doesn't pause when asleep.

SystemUtil.h for interface:

#import <Foundation/Foundation.h>

@interface SystemUtil : NSObject

- (time_t)uptime;

@end

SystemUtil.m for implementation:

#import "SystemUtil.h"
#include <sys/sysctl.h>

@implementation SystemUtil

- (time_t)uptime
{
    struct timeval boottime;
    int mib[2] = {CTL_KERN, KERN_BOOTTIME};
    size_t size = sizeof(boottime);
    time_t now;
    time_t uptime = -1;

    (void)time(&now);

    if (sysctl(mib, 2, &boottime, &size, NULL, 0) != -1 && boottime.tv_sec != 0) {
        uptime = now - boottime.tv_sec;
    }
    return uptime;
}

@end

And don't forget to include a <Project>-Bridge-Header.h with the following content so that you can use the ObjC class from Swift (<Project> is your project name):

#import "SystemUtil.h"

Upvotes: 2

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