+ // TODO: Regex
+ if( strcmp(tmp, "ok") == 0 ) {
+ // We think dispense worked
+ // - The machine returns 'ok' if an empty slot is dispensed, even if
+ // it doesn't actually try to dispense (no sound)
+ return 0;
+ }
+
+ printf("Machine returned unknown value '%s'\n", tmp);
+
+ return -1;