custom functions SQLite with Mono
c#, mono, sql, sqlite, xamarin.ios
Solution
Look at the Reverse Callbacks paragraph of the page that the error reports: in practice you need to apply the MonoPInvokeCallbackAttribute attribute to the method (and it needs to be made static).
This is a limitation on iOS devices, because they don't support JIT compilers.
Problem
is there a way to add SQLite custom function using Mono? (Mono.Data.Sqlite) I tried to add distance function that returns the distance between two geo locations ``` [SqliteFunctionAttribute(Name = "distance", Arguments = 4, FuncType = FunctionType.Scalar)] class SqliteDistance : SqliteFunction { public override object Invoke(object[] args) { double radius = 6367; double lat1 = System.Convert.ToDouble(args[0]); double lng1 = System.Convert.ToDouble(args[1]); double lat2 = System.Convert.ToDouble(args[2]); double lng2 = System.Convert.ToDouble(args[3]); return radius * 2 * Math.Asin( Math.Min(1, Math.Sqrt( ( Math.Pow(Math.Sin((lat2* (Math.PI / 180) - lat1 * (Math.PI / 180) ) / 2.0), 2.0) + Math.Cos(lat1* (Math.PI / 180)) * Math.Cos(lat2* (Math.PI / 180)) * Math.Pow(Math.Sin(( lng2* (Math.PI / 180)-lng1* (Math.PI / 180)) / 2.0), 2.0) ) ) ) ); } } ``` and it gives me an error: Attempting to JIT compile method '(wrapper native-to-managed) Mono.Data.Sqlite.SqliteFunction:ScalarCallback (intptr,int,intptr)' while running with --aot-only. See http://docs.xamarin.com/ios/about/limitations for more information.