Updated code:

This is purported to work officially.

#if TARGET_IPHONE_SIMULATOR

NSString *hello = @"Hello, iPhone simulator!";

#elif TARGET_OS_IPHONE

NSString *hello = @"Hello, device!";

#else

NSString *hello = @"Hello, unknown target!";

#endif

Original post (since deprecated)

This code will tell you if you are running in a simulator.

#ifdef __i386__

NSLog(@"Running in the simulator");

#else

NSLog(@"Running on a device");

#endif

Not pre-processor directive, but this was what I was looking for when i came to this question;

NSString *model = [[UIDevice currentDevice] model];

if ([model isEqualToString:@"iPhone Simulator"]) {

    //device is simulator

}

The best way to do this is:

#if TARGET_IPHONE_SIMULATOR

and not

#ifdef TARGET_IPHONE_SIMULATOR

since its always defined: 0 or 1

In case of Swift we can implement following

We can create struct which allows you to create a structured data

struct Platform {

    static let isSimulator: Bool = {

        #if arch(i386) || arch(x86_64)

            return true

        #endif

        return false

    }()

}

Then If we wanted to Detect if app is being built for device or simulator in Swift then .

if Platform.isSimulator {

    // Do one thing

}

else {

    // Do the other

}

THERE IS A BETTER WAY NOW!

As of Xcode 9.3 beta 4 you can use #if targetEnvironment(simulator) to check.

#if targetEnvironment(simulator)

//Your simulator code

#endif

UPDATE

Xcode 10 and iOS 12 SDK supports this too.

All those answer are good, but it somehow confuses newbie like me as it does not clarify compile check and runtime check. Preprocessor are before compile time, but we should make it clearer

This blog article shows How to detect the iPhone simulator? clearly

Runtime

First of all, let’s shortly discuss. UIDevice provides you already information about the device

[[UIDevice currentDevice] model]

will return you “iPhone Simulator” or “iPhone” according to where the app is running.

Compile time

However what you want is to use compile time defines. Why? Because you compile your app strictly to be run either inside the Simulator or on the device. Apple makes a define called TARGET_IPHONE_SIMULATOR. So let’s look at the code :

#if TARGET_IPHONE_SIMULATOR



NSLog(@"Running in Simulator - no app store or giro");



#endif

The previous answers are a little dated. I found that all you need to do is query the TARGET_IPHONE_SIMULATOR macro (no need to include any other header files [assuming you are coding for iOS]).

I attempted TARGET_OS_IPHONE but it returned the same value (1) when running on an actual device and simulator, that's why I recommend using TARGET_IPHONE_SIMULATOR instead.

In swift :

#if (arch(i386) || arch(x86_64))

...            

#endif

From Detect if app is being built for device or simulator in Swift

I had the same problem, both TARGET_IPHONE_SIMULATOR and TARGET_OS_IPHONE are always defined, and are set to 1. Pete's solution works, of course, but if you ever happen to build on something other than intel (unlikely, but who knows), here's something that's safe as long as the iphone hardware doesn't change (so your code will always work for the iphones currently out there):

#if defined __arm__ || defined __thumb__

#undef TARGET_IPHONE_SIMULATOR

#define TARGET_OS_IPHONE

#else

#define TARGET_IPHONE_SIMULATOR 1

#undef TARGET_OS_IPHONE

#endif

Put that somewhere convenient, and then pretend that the TARGET_* constants were defined correctly.

Works for Swift 4 and Xcode 9.4.1

Use this code:

#if targetEnvironment(simulator)

   // Simulator

#else

   // Device

#endif

Has anyone considered the answer provided here?

I suppose the objective-c equivalent would be

+ (BOOL)isSimulator {

    NSOperatingSystemVersion ios9 = {9, 0, 0};

    NSProcessInfo *processInfo = [NSProcessInfo processInfo];

    if ([processInfo isOperatingSystemAtLeastVersion:ios9]) {

        NSDictionary<NSString *, NSString *> *environment = [processInfo environment];

        NSString *simulator = [environment objectForKey:@"SIMULATOR_DEVICE_NAME"];

        return simulator != nil;

    } else {

        UIDevice *currentDevice = [UIDevice currentDevice];

        return ([currentDevice.model rangeOfString:@"Simulator"].location != NSNotFound);

    }

}

To include all types of "simulators"

NSString *model = [[UIDevice currentDevice] model];

if([model rangeOfString:@"Simulator" options:NSCaseInsensitiveSearch].location !=NSNotFound)

{

    // we are running in a simulator

}

With Swift 4.2 (Xcode 10), we can do this

#if targetEnvironment(simulator)

  //simulator code

#else 

  #warning("Not compiling for simulator")

#endif

For Swift 4.2 / xCode 10

I created an extension on UIDevice, so I can easily ask for if the simulator is running.

// UIDevice+CheckSimulator.swift



import UIKit



extension UIDevice {



    /// Checks if the current device that runs the app is xCode's simulator

    static func isSimulator() -> Bool {        

        #if targetEnvironment(simulator)

            return true

        #else

            return false

        #endif

    }

}

In my AppDelegate for example I use this method to decide wether registering for remote notification is necessary, which is not possible for the simulator.

// CHECK FOR REAL DEVICE / OR SIMULATOR

if UIDevice.isSimulator() == false {



    // REGISTER FOR SILENT REMOTE NOTIFICATION

    application.registerForRemoteNotifications()

}

My answer is based on @Daniel Magnusson answer and comments of @Nuthatch and @n.Drake. and I write it to save some time for swift users working on iOS9 and onwards.

This is what worked for me:

if UIDevice.currentDevice().name.hasSuffix("Simulator"){

    //Code executing on Simulator

} else{

    //Code executing on Device

}

/// Returns true if its simulator and not a device

public static var isSimulator: Bool {

    #if (arch(i386) || arch(x86_64)) && os(iOS)

        return true

    #else

        return false

    #endif

}

SWIFT 4 Solution

static let isSimulator: Bool = {

    return TARGET_OS_SIMULATOR == 1

}()

TARGET_OS_SIMULATOR is located in Darwin.TargetConditionals.swift file.

Apple has added support for checking the app is targeted for the simulator with the following:

#if targetEnvironment(simulator)

let DEVICE_IS_SIMULATOR = true

#else

let DEVICE_IS_SIMULATOR = false

#endif

if nothing worked, try this

public struct Platform {



    public static var isSimulator: Bool {

        return TARGET_OS_SIMULATOR != 0 // Use this line in Xcode 7 or newer

    }



}