Linux terminal pipe to my C++ program

Question

I'm not sure about the terminology, and when I googled this I got many misleading results. I just need a push and I'll be fine.

How can put my program as a target to piping in linux terminal?

Say I wrote a C++ program MyProg

I would like to be able to do something like

$ ls | ./MyProg

Could you please give me a hint to what function/stream can be used for this?

Answer 1

Piping, as you call it, is nothing special in Linux, that's why you do not find it.

What the pipe does is to redirect the standard output ( stdout ) of one program to the standard input ( stdin ) of another. So simply read the standard input, and you will find the text there. You an use std::cin if you want to go the C++ way, or *scanf() in C mode.

If you want to know if stdin refers to the actual terminal or some redirection, you can use isatty(0) (0 is the fd of stdin, there is a constant somewhere but I can't remember the name, while everybody know that stdin is 0).

Answer 2

You should handle standard input (stdin) , output (stdout) and error (stderr) in your application. They have reserved file descriptor numbers. Please refer to following link File descriptor Wiki