template<typename T> int globalVar = 123; ^^^---- apparent type int^^^^^^^^^^^^^^^^^^^^^^^^^^^^--- effective type (int)<T> [ with T resovled at instantiation site](int)<T> : is not a correct C++, it is invented for the purpose of this talk.Soauto var = globalVar<double>;Apparent type of var is int.But effective type is (int)<double>, in words it say, a variable template of type int instantiated with type double.>>>Thank you Sébastien for the perfect short summary. Oops, Sebastian, not Sébastien, sorry :)Sent from my Galaxy-------- Original message --------From: Sebastian Wittmeier via Std-Proposals <std-proposals_at_[hidden]> Date: 7/30/24 6:05 PM (GMT+04:00) To: std-proposals_at_[hidden] Cc: Sebastian Wittmeier <wittmeier_at_[hidden]> Subject: Re: [std-proposals] Function overload set type information loss
template<typename T>int globalVar = 123; This is a variable template; globalVar<double> var; You have kind of 3 types here, not 2: globalVar<double>, double and int As far as I understand, you want to extract the template parameter double from globalVar<double>, before it is resolved. But you also want to get it from wherever it is used with auto:auto var = globalVar<double>; In this case, you want to get double from var.