It means that a call to that function with an optional will unwrap the optional before it is used.
That is quite neat when dealing with C-API’s because often you will receive a pointer from a C-function which is optional to account for the fact that it can be NULL (= nil). By using a forced unwrapped input parameter you are saved the trouble of unwrapping all these pointers when using them as input for other C-APIs. In short, it makes it easier to interface with C-API’s. Note that there is some under-the-hood magic going on because a C-pointer is an unboxed value, while a ‘normal’ optional is a boxed value. Regards, Rien Site: http://balancingrock.nl Blog: http://swiftrien.blogspot.com Github: http://github.com/Swiftrien Project: http://swiftfire.nl > On 10 Jan 2017, at 01:23, Ethin Probst via swift-users > <swift-users@swift.org> wrote: > > Hello all, > I was wondering what an exclamation mark in a swift parameter listing > means. For instance, I used Elements Oxidizer Live to translate some > C# code into Swift. Reviewing it, I found the following (among > others): > @DllImport("ScriptHookV.dll") > private static __extern func scriptRegister(_ module: System.IntPtr!, > _ LP_SCRIPT_MAIN: LP_SCRIPT_MAINDelegate!) > What I'm wondering is what does the '!' in that list of parameters > mean? I also saw it when writing another program: > func MainForm_Load(_ sender: System.Object!, _ e: System.EventArgs!) { > // ... > } > I don't recall the swift book teaching you what that means, so could > someone tell me what those mean? > -- > Signed, > Ethin D. Probst > _______________________________________________ > swift-users mailing list > swift-users@swift.org > https://lists.swift.org/mailman/listinfo/swift-users _______________________________________________ swift-users mailing list swift-users@swift.org https://lists.swift.org/mailman/listinfo/swift-users
