Read a character from the keyboard
unsigned int SLang_getkey (void);
The SLang_getkey reads a single character from the terminal
and returns it. The terminal must first be initialized via a call
to SLang_init_tty before this function can be called. Upon
success, SLang_getkey returns the character read from the
terminal, otherwise it returns SLANG_GETKEY_ERROR.
SLang_init_tty, SLang_input_pending, SLang_ungetkey