std::string and Upp::String are two completely different classes.

So the question is, why do you even use std::string in U++ application (or the other way around, why don't you stick solely to std::string, if you want to keep usage of U++ low and having that part of source usable without U++ Core too).

If your app is strongly U++ dependent, I would go for Upp::String only (except places where you call some external library, which has input as std::string, at that single point I would convert the String to string, but otherwise I would keep internally everything in String).

I often write clean C++ libraries in TheIDE (to be compiled on phone platforms, so I don't use Upp at all), then I use std::string only.

Your mixed way is certainly possible too, but I think it's not giving you any advantage, just confusing.

Hi,

the conversion from Upp::String to std::string is explicit by the function member ToStd()

String s_upp;
std::string s_std = s_upp.ToStd();

IMO the easier way is to avoid std::string, Upp::String is simpler, faster.

here a solution for this error:

String Min = Tm.Mid(2,2);
String Tmz = Hr + ":" + Min + ":" + Tm.Mid(4,2);
count<<=Tmz;

I am still getting errors this time when compiling with MS15 or MINGW

Under upp 9701 it compiles OK with either compiler.
Under upp 9801 or 9861 it does not and I get
: error C2676: binary '<<=': 'Upp::String' does not define this operator or a conversion to a type acceptable to the predefined operator

ln<<= GGA2decAng(ln);

ln<<GGA2decAng(ln);