I think I didn't explain myself. What you say is true, but even if your program doesn't see any input, you can (the kernel n_tty line discipline) edit the inpu

I think I didn't explain myself. What you say is true, but even if your program doesn't see any input, you can (the kernel n_tty line discipline) edit the input (delete it). So if I do print() read() print() read() the reads will only be able to edit what has been input since that particular syscall.