Using sysctlbyname() from Swift

Question

I’m using the code from this Gist to determine which iOS device (e.g. iPhone5,1) my app is running on:

- (NSString *)platform {     size_t size;     sysctlbyname("hw.machine", NULL, &size, NULL, 0);     char *machine = malloc(size);     sysctlbyname("hw.machine", machine, &size, NULL, 0);     NSString *platform = [NSString stringWithUTF8String:machine];     free(machine);     return platform; } 

The Swift documentation indicates that C data types are well-supported, but it doesn’t say anything about C functions. Is there a pure Swift way to retrieve the machine identifier, or will I have to bridge into Objective-C for this?

Answer 1

You can do the same in Swift (error checking omitted for brevity):

func platform() -> String {     var size : Int = 0 // as Ben Stahl noticed in his answer     sysctlbyname("hw.machine", nil, &size, nil, 0)     var machine = [CChar](count: size, repeatedValue: 0)     sysctlbyname("hw.machine", &machine, &size, nil, 0)     return String.fromCString(machine)! } 

Update for Swift 3:

func platform() -> String {     var size = 0     sysctlbyname("hw.machine", nil, &size, nil, 0)     var machine = [CChar](repeating: 0,  count: size)     sysctlbyname("hw.machine", &machine, &size, nil, 0)     return String(cString: machine) } 

Answer 2

As of Swift 1.2 (Xcode 6.3 beta-2), @MartinR's code above needs to be modified slightly. sysctlbyname needs a CChar array (i.e. C string) for the first parameter, and an Int (instead of Uint) for the "size" parameter.

func platformModelString() -> String? {     if let key = "hw.machine".cString(using: String.Encoding.utf8) {         var size: Int = 0         sysctlbyname(key, nil, &size, nil, 0)         var machine = [CChar](repeating: 0, count: Int(size))         sysctlbyname(key, &machine, &size, nil, 0)         return String(cString: machine)     }     return nil } 

EDIT: Updated 2017-01-04 for Swift 3 syntax