C program output should go to console, but should not be redirectable

Question

I want my_custom_print() output to appear on console. But if the program's stderror or stdout is redirected from shell, they should get redirected (as normal), but the output from my_custom_print() should get ignored.

Is it possible to write my_custom_print() satisfying above condition ? If possible, how?

Answer 1

You can try opening /dev/tty, but it doesn't necessarily exist, if your program run from the environment with no tty.

Answer 2

Maybe isatty or /dev/tty could be useful to you.