Portability

So, I've been trying to learn C, and I don't seem to understand the need of portability. Like, people suggest I don't use conio.h or graphics.h because they are not standard, and therefore, not portable. But is this only true as far as the source code goes? Like, after the program has been compiled, will it run on any computer that can run executables? Or will the computer need to somehow not be compatible with the program due to not having some sort of way to read conio.h or graphics.h?

It will run on your computer only. It cannot run on anyone else's computer because this would be a violation of international copyright law.

International Stallman Law

If you're using conio.h I don't think you have to worry about portability, because no one else will want to use whatever mess you can code.

I am the great conio!
I need SICP for my bunghole!

Holy shit. At least read the Wikipedia page about software before posting here. ``Thanks!''

To use your example, conio.h is Unix-only, meaning any program that uses it cannot be compiled to run on Windows.

Now fuck off.