Enables/disables terminal echo.
Curses Library (libcurses.a)
#include <curses.h>
int echo(void);
int noecho(void);
The echo subroutine enables Echo mode for the current screen. The noecho subroutine disables Echo mode for the current screen. Initially, curses software echo mode is enabled and hardware echo mode of the tty driver is disabled. The echo and noecho subroutines control software echo only. Hardware echo must remain disabled for the duration of the application, else the behaviour is undefined.
Upon successful completion, these subroutines return OK. Otherwise, they return ERR.
echo();
noecho();