Hi Laura,
As you found, there's no real consistency among implementations
as to the exact values. Try to write something that works with both
PDCurses and ncurses, for example, and you'll have some code that
looks like
#ifdef KEY_EXIT
if( key == KEY_EXIT)
do_stuff( );
#endif
#ifdef KEY_B3
if( key == KEY_B3)
do_b3_stuff( );
#endif
I see I have an '#ifdef ALT_0' in one bit of code, so even that cannot
be uniformly relied upon.
Now, in terms of what we _should_ do... I guess I'd rather like the
idea that we minimize the number of keys. Rather than have an 'A' and
an 'Alt-A', you'd have an A with the Alt modifier set. I say that
despite having added a hundred or so key codes to the Win32a flavor
of 'curses.h' (look in that file for the section starting with CTL_SEMICOLON).
I figure that if we have all these keys (I have a keyboard with 'browser
back/forward', 'refresh', 'search', etc. keys), we ought to be able
to access them. But I do have KEY_VOLUME_DOWN, KEY_SVOLUME_DOWN,
KEY_CVOLUME_DOWN, and KEY_AVOLUME_DOWN as four separate key codes.
Incidentally, you'll also see that in the Win32a version of 'curses.h',
the return values are relative to KEY_OFFSET. The reason for this is that
PDCurses' "usual" values assume a non-wide version, and they start at
0x100. Try making a Unicode build, and there will be collisions: if you
get, say, 0x16B, did your user hit KEY_MESSAGE, or an 's with acute
accent'? Further details at
http://projectpluto.com/win32a.htm#2014mar1
, but essentially, we put the KEY_ values into Unicode's Private Use
Area, where it cannot collide with any actual key value somebody using
an Absurdistani keyboard layout might generate.
-- Bill
On 04/08/2015 03:35 PM, LM wrote:
I'm trying to double-check that the keys are mapping properly for SDL.
The only documentation on keys that I could turn up was at:
http://pubs.opengroup.org/onlinepubs/7908799/xcurses/curses.h.html
Does anyone have a list of what key values should be returned for what
key combinations. curses.h has some values defined such as ALT_0 -
ALT_9 and ALT_A - ALT_Z. A curses application like hexedit uses
CONTROL_A - CONTROL_Z and CONTROL_SLASH which aren't even documented
by pdcurses. Checking the various back-ends of pdcurses, even its key
translations don't seem to agree with each other. Some pdcurses
back-ends return ALT_BSLASH and some return the backslash with alt
modifier set.
Does anyone know where to find documentation on what should be valid
key return values or does anyone have recommendations on how they'd
like to see this consistently handled? It would be nice to have
better compatibility with what ncurses does if possible. Thanks.
