A historically common and still prevalent convention uses the ETX character convention to interrupt and halt a program via an input data stream, usually from a keyboard.
ɐ hɪstˈɔːɹɪkli kˈɑːmən ænd stˈɪl pɹˈɛvələnt kənvˈɛnʃən jˈuːsᵻz ðɪ ˌiːtˌiːˈɛks kˈæɹɪktɚ kənvˈɛnʃən tʊ ˌɪntɚɹˈʌpt ænd hˈɔlt ɐ pɹˈoʊɡɹæm vˈaɪəɹ ɐn ˈɪnpʊt dˈeɪɾə stɹˈiːm, jˈuːʒuːəli fɹʌm ɐ kˈiːboːɹd.