How portable is my C++ code in UE4?

Are there any restrictions to C++ programing in UE4 regarding portability?
What about publishing to HTML5 or Android. Will all of my C++ code work on all UE4 supported platforms ?
Is not, is there any C++ technical guideline for portability document ?

Thanks

As long as you gonna use Unreal APIs (which also includes basic things like math and file io) engine will deal with that for you. Ofcorse there might be features that on’t work on some platform, but it is the same as with Blueprint programming, you should gen info on that for each platform documentation.

The steps toward publishing from UE4 to HTML5/WebGL are still a bit rough, but you can get started here:
https://docs.unrealengine.com/latest/INT/Platforms/HTML5/index.html

At the moment, Apple does not support WebGL on its mobile devices. WebGL - 3D Canvas graphics | Can I use... Support tables for HTML5, CSS3, etc

Ok, from the answers I got, I assume there is no C++ portability technical document yet. So this is going to be more like, code until it breaks a specified platform to find out…

Rather goal is to make you not care about this, to make it seamless. Unreal APIs are made to be portable, as long as you use them project will build anyway regardless of platform, some of them might be feature lacking mostly on graphics fields as Mobile GPUs lacking behind Desktop GPUs, which actually effect content creators then C++ programmers.

Theres platfrom related documents which should have notes what is unsupported:

https://docs.unrealengine.com/latest/INT/Platforms/Android/index.html

https://docs.unrealengine.com/latest/INT/Platforms/HTML5/index.html

Windows and OS X are no diffrent and can use Engine at it fullest, only difference is between using DX10/OpenGL3.x and DX11/OpenGL compatible GPUs the 1st ones won’t support all graphical features