wjc@ho5cad.att.com (William J Carpenter) (08/07/89)
[Environment: both sun3 and sun4, both sunOS 4.0.1 and 4.0.3]
When I am running suntools on the console of a sun (where else?),
there is some stty problem with canonical mode. Somehow, my stty
changes for the special characters are being partially ignored.
1. $ stty intr ^C
2. $ sleep 10
3. (hit ^C, the sleep is interrupted, as expected)
4. $ stty intr ^X
5. $ sleep 10
6. (hit ^C, the sleep is interrupted, as expected)
7. $ stty werase ^_
8. $ stty intr ^W
9. $ sleep 10
10. (hit ^W, the sleep is *not* interupted;
hit ^C, also no effect)
11. $ stty -icanon
12. $ sleep 10
13. (hit ^W, the sleep is interupted, as expected)
In steps 1-3, I use the BSD default interupt character ^C, and
everything works as expected. In steps 4-6, I use ^X, which is not
one of the pre-defined "special" characters for icanon. This also
works.
In steps 7-10, I use ^W. This is normally the BSD word-erase
character, so I first clobber werase. This is the problem. Even
though `stty -a` shows the settings one expects, the ^W won't work as
an interrupt character.
In steps 11-13, I just turn off icanon and things go back to normal.
Of course, I can't operate in -icanon mode all the time.
So, here is what I think is a summary of the problem:
1. When in suntools, some layer of this massive window conspiracy is
noticing whether or not "icanon" is set. If so, it tries to do
something with what it thinks are the special characters.
2. For example, if it sees ^W, it tries to do word erase, even though
I have set stty so that ^W is interrupt. So, ^W doesn't work as
interrupt.
3. When it sees ^C (the default interrupt), it passes it on down to
our level. Since we have no special meaning for ^C (we overlaid it
with ^W), that doesn't work as interrupt either. [Another possibility
is that there is some hack in there so that "our level" doesn't
interpret the icanon special characters, knowing that the mystery
level already took care of it. Dunno.]
4. I have tried this with some of the other special characters
(besides interrupt) with the same problem. It looks like some layer
doesn't believe in changing them to whatever you want.
5. This is not a problem on the naked console or while rlogin'd. It
only happens under suntools. (BTW, if you are under suntools and
rlogin to someplace, even back to the same machine, rlogin uses
-icanon, so the problem is hidden. A good way to fake yourself out,
though.)
I have no clue how to fix this. Got any ideas? This is quite
annoying.
--
Bill Carpenter att!ho5cad!wjc or attmail!bill