This function specifies that future file operations which operate in the save game area (i.e. all file writes, and reads from files that aren't in the bundle area) will be associated with the specified user ID pointer. This can be called as often as necessary to redirect save data to the appropriate user, or you can use the constant pointer_null to save to the generic machine storage area.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 user ID (a pointer) to set for saving, or pointer_null
if xboxlive_get_savedata_user() != user_id
The above code checks to see if a user is currently assigned as the save target, and if they are not then they are assigned.