Mutable Global Variable in Swift

Question

I would like to know if there is a way to create a mutable global variable in Swift? I know that I can declare constants, but I want to change the value.

Thanks

@Kirsteins couldn't that approach lead to weird behaviours when you try to set the variable from multiple sources at the same time? — Dániel Nagy
– Dániel Nagy, Commented Apr 10, 2015 at 13:16
@DánielNagy, only if you are writing multi-threaded code. In that case you better know what you are doing, and add synchronization code. — Duncan C
– Duncan C, Commented Apr 10, 2015 at 13:41
@DánielNagy Thread safety is not exclusive to this question. It should be taken into account when dealing with any variable resources. — Kirsteins
– Kirsteins, Commented Apr 10, 2015 at 13:50

Duncan C · Accepted Answer · 2015-04-10 13:43:47Z

1

In swift, you declare variables with var and constants with let.

If you want a global variable, create it a the top of a file, outside of the definition of any enclosing class/struct/enum/etc.

If you will access that variable from multi-threaded code as @DánielNagy mentions in his comment, it's more complex. However accessing global variables from concurrent code is best avoided.

answered Apr 10, 2015 at 13:43

Duncan C

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Gabriel M. · Accepted Answer · 2017-03-24 08:41:31Z

0

you can write

class myViewController : UIViewController{
struct GlobalVar{
static var myName : String?
}
override func viewDidLoad(){
super.viewDidLoad()
}
}

in any view controller and access it anywhere by:

//Another VC viewDidload
GlobalVar.myName = "Hello"
print(GlobalVar.myName)

answered Mar 24, 2017 at 8:41

Gabriel M.

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