nothing at all .. C++ is a programming language and those of us who do any at all usually just use a plaintext editor.
but that is about the specifics of coding "for" the different platforms.. not the methods of actually writing the code.. using as the writing platform wincrap, linux, unix, beos.. whatever. I script in python, perl and ruby.. platform independent where possible.. anybody who hacked an old black xbox has probably used a couple of applications I wrote with Ruby for that platform.. I don't code for wincrap at all.. who would?.. it's proprietary garbage and the sooner it and it's oneclick obsessed sheeple are gone the better the world will be. it puzzles me why people even come asking such totally off mission questions here in a dead area of an entertainment oriented site.. there must be better places... unless of course it's spambots...
C++ is just a computer programming language that is well defined in the norm ISO/IEC 14882:1998. So every compiler which calls itself C++-Compiler will be able to interpret the syntax, that the grammar (specified in that norm) produces -> No syntax-difference! So the main-differences you will come across, are the supplied libraries, tools and frameworks; No MFC on Linux ;-) As long as you use standard C++, your program will compile under Windows as well as under Linux or any other environment. If you are interested in "cross-platform C++" you may want to take a look at a project called widgets (ask Google) that wraps platform-specific things like thread-, mouse- and display handling in a common way, so that you are able to build even cross-platform GUI-Apps.