Ncurses reading numpad keys and escapes

Question

I am trying to use ESC to exit a program using getch (). I created a small program to demonstrate my problem.

#include <ncurses.h> int main(void) { int key = 0; initscr(); noecho(); keypad(stdscr, TRUE); do { key = getch(); clear(); mvprintw(0, 0, "Key = %d\n", key); refresh(); } while (key != 27); clear(); refresh(); endwin(); return 0; } 

I am trying to allow the user to use the arrow keys or the keyboard (whichever is more convenient)

the problem is the keyboard (whether numlock is on or not). When I compile and run the program and try to use the numpad keys in this simple test, it exits as soon as I touch the numpad key. If I remove the while condition (key! = 27) (esc is 27), it reads the keys and displays their numbers. Why does it exit the loop when the numpad keys are registered as

 ENTER 343 UP 120 DOWN 114 LEFT 116 RIGHT 118 

Any help is much appreciated!

Answer 1

I found a fix in the source for the Dungeon Crawl Stone Soup. He basically sets up key codes for them.

{DCSS-dir} /source/libunix.cc (333)

 define_key("\033Op", 1000); define_key("\033Oq", 1001); define_key("\033Or", 1002); define_key("\033Os", 1003); define_key("\033Ot", 1004); define_key("\033Ou", 1005); define_key("\033Ov", 1006); define_key("\033Ow", 1007); define_key("\033Ox", 1008); define_key("\033Oy", 1009); // non-arrow keypad keys (for macros) define_key("\033OM", 1010); // Enter define_key("\033OP", 1011); // NumLock define_key("\033OQ", 1012); // / define_key("\033OR", 1013); // * define_key("\033OS", 1014); // - define_key("\033Oj", 1015); // * define_key("\033Ok", 1016); // + define_key("\033Ol", 1017); // + define_key("\033Om", 1018); // . define_key("\033On", 1019); // . define_key("\033Oo", 1020); // - // variants. Ugly curses won't allow us to return the same code... define_key("\033[1~", 1031); // Home define_key("\033[4~", 1034); // End define_key("\033[E", 1040); // center arrow 

Answer 2

The XTERM terminal emulator sends an escape for certain numpad keys if Num Lock is off.

You can enable Num Lock, use something other than numpad, use something other than ESC to break your loop, or try to find a terminal emulator that doesn't. The program cannot distinguish between ESC and some numpad characters when Num Lock is disabled within your terminal emulator.