This function converts the User ID pointer into a string.IMPORTANT! This function is only valid when exporting using the UWP target for the Xbox One and it requires you to have checked the Enable XBox Live option in the UWP Game Options.
Argument Description user_id The ID pointer of the user to check.
var _uid = xboxlive_user_for_pad(0);
uid_string = xboxlive_user_id_for_user(_uid);
The above code gets the user ID pointer for the user assigned to the gamepad  slot, and then saves that user ID as a string to an instance variable.