Question

For an exercise about termcaps, I have to write a program that will display a list of items and let the user to select some of them. The program will then output the selected items separated with a space. The program can be called like this:

$> ./my_program foo1 foo2 foo3

or like this:

$> ls `my_program foo1 foo2 foo3`

My program works well in the first case, but in the second case, the stdout of my_program is intercepted by the backticks and will not show up on the terminal. I know that the program is running well since I got the expected result from ls if I select some items blindly.

In my program, I can’t use any built-in functions excepted the following:
• ioctl
• tcsetattr
• tcgetattr
• tgetent
• tgoto
• tputs
• tgetstr
• tparm
• open
• close
• write
• malloc
• free
• read
• exit
• signal

How can I display my_program’s stdout to the user when called like in the second case ?

EDIT:
The only option I found is to output everything to stderr and output the selected items to stdout…

Answer 1

You can open and write to /dev/tty in my_program and it will be only to the terminal not to the redirected stdout.