At 7/7/2002 6:10:00 PM, Jeremy Smith wrote: >I have run into a bit of a problem. I use the Curses function getch() in >my program, for keys such as 'n' or Alt+'n' but how do I detect these >combinations: > >Ctrl+n >Alt+Shift+n >Ctrl+Alt+n >Ctrl+Alt+Shift+n
>I imagine there must be some kind of flag to return Shift+Alt+2 as an >actual keycode (which is different from Shift, Alt or 2), but I don't >know how. :-( I checked the header for file for curses.h and they appear to list all the standard scan codes you can get back from a keyboard, including some ALT combinations and a few of the Control combinations. Then I checked the Windows implementation for getting a character. In pdckbd.c the routine win32_kbhit calls ReadConsoleInput. The shift, alt, control and other status keys are returned from this function in the dwControlKeyState. The PDC_get_bios_key reports what key is pressed using the two kptab tables (kptab and ext_kptab), so if the combination is not in the table, you probably aren't seeing it. You may be able to add some definitions to the tables if something is missing. There's also some code in the same routine that sets the states (BUTTON_SHIFT, BUTTON_CONTROL, BUTTON_ALT), but this appears to be for mouse input. So you can check these keys in the MOUSE_STATUS structure. This only pertains to the Windows implementation. Every platform has a unique way of figuring out which keys are pressed. In 16 bit DOS, I used to change the state of shift, caps lock and num lock by changing the settings at the hex 417 address. This only works for real mode programs. Many of the new Windows compilers don't even allow you to access bios or memory directly with functions any more. The 16 bit location at hex 417 and hex 418 indicates that the right shift has been pressed by setting the highest bit at the 417 address, the left shift, by setting the second highest bit in the byte, the ctrl key by setting the next highest and the alt key by the next highest after that. The 418 address holds the status of whether or not the right or left alt and control keys were pressed. It appears as though you may have to make some modifications to your particular version of curses to get exactly what you want. Curses is a very portable user interface, thus it often supports the lowest common denominator of features on some platforms. By the way, I remember reading that there was work underway for a new curses standard that included international character support. Has anyone heard anything further on this effort? Best wishes. Laura Michaels http://www.distasis.com
