Unless noecho has been set, these routines echo the character into the designated window.
If the window is not a pad and has been moved or modified since the last call to wrefresh, wrefresh will be called before another character is read.
If keypad is enabled, these functions respond to the pressing of a function key by setting the object pointed to by wch to the keycode assigned to the function key, and returning KEY_CODE_YES. If a character (such as escape) that could be the beginning of a function key is received, curses sets a timer. If the remainder of the sequence does arrive within the designated time, curses passes through the character; otherwise, curses returns the function key value. For this reason, many terminals experience a delay between the time a user presses the escape key and the time the escape is returned to the program.
The keycodes returned by these functions are the same as those
returned by wgetch:
.IP • 4 The predefined function keys are listed in <curses.h> as macros with values outside the range of 8-bit characters. Their names begin with KEY_.
.IP • 4 Other (user-defined) function keys which may be defined using define_key(3X) have no names, but also are expected to have values outside the range of 8-bit characters.
The unget_wch function pushes the wide character wch back onto the head of the input queue, so the wide character is returned by the next call to get_wch. The pushback of one character is guaranteed. If the program calls unget_wch too many times without an intervening call to get_wch, the operation may fail.
Applications should not define the escape key by itself as a single-character function.
When using get_wch, wget_wch, mvget_wch, or mvwget_wch, applications should not use nocbreak mode and echo mode at the same time. Depending on the state of the tty driver when each character is typed, the program may produce undesirable results.
Upon successful completion, unget_wch returns OK. Otherwise, the function returns ERR.