Visual Studio 2015 <=> QtCreator 5 (c++) code portability

I'm working in Visual Studio 2015 and creating some projects using std:: libraries, as well as c++11 features like "nullptr", "initializer list"s and "auto" keyword. I also use "stdafx" precompiled header. The std:: components that I use are: <vector>, <string>, <chrono>, <stdio>, <iomanip>, <iostream>, <fstream>, <strsafe>, <math.h>, <thread>, <mutex>, <ctime>

I'm going to provide my .h and .cpp codes for other people (who probably don't use VS2015) in the close future and there are some questions:

1) For what things should I have prepared before I start to provide them my code?
2) What should I keep in my mind if want my code to work properly in Linux environment (using QtCreator) in the future?
3) These libraries that I mention, is this everything okay (compatible && portable) if I use them and if I want my code to be portable for linux and windows versions of QtCreator C++11 environment?
4) What can be wrong and what should I also keep in my mind?