creating unbuffered, invisible routine for unix

[Little Bobby Tables]

so im working with threads, and i want to make it so that whenever someone hits a letter, for example, 'q', it performs an action, such as quit. i can do this quite easily, and i have a function to turn off the input buffer (resulting in unbuffered input) but it still shows the letter on the terminal. how can i make it so it doesnt show up?

[ne555]

noecho()