On 4/26/16 2:54 PM, [email protected] wrote:
> I have a short example program that I attached. I haven't added
> SIGWINCH handling yet. You can see that I use siglongjmp to get out of
> the SIGINT handler - a tip I found on stackoverflow - and then I try a
> few miscellaneous Readline cleanup functions. I'm trying to get
> behavior like Bash - ^C should cancel anything I've entered on a line,
> an give me a new prompt. (I notice that GDB has different, somewhat
> annoying behavior, of keeping the input line on ^C)
>
> The example that I wrote has a bug which both R and Python suffer
> from. The problematic behavior is that when the user hits ^C during a
> reverse-isearch, the last isearch proposal is kept as a "hidden" input.
>
> For R, I reported this bug in
> <https://bugs.r-project.org/bugzilla/show_bug.cgi?id=16603>.
>
> I'm a bit curious to know if this bug has always been present, or if
> it appeared with Readline 6.3 or some other recent version.
It's always been present.
You can fix your problem in readline-6.3 and earlier by making your code
look like this:
if(sigsetjmp(env, 1)) {
rl_free_line_state ();
rl_cleanup_after_signal ();
RL_UNSETSTATE(RL_STATE_ISEARCH|RL_STATE_NSEARCH|RL_STATE_VIMOTION|RL_STATE_NUMERICARG|RL_STATE_MULTIKEY);
rl_done = 1;
rl_callback_handler_remove ();
printf("\n");
}
If you want a little more control, you can replace rl_done = 1 with
rl_line_buffer[rl_point = rl_end = rl_mark = 0] = 0;
That part clears out the line buffer. The call to UNSETSTATE cleans up the
readline state it uses to keep track of where it is between calls to
rl_callback_read_char(). Without that, readline's state tells it it's
still in the middle of the incremental search.
#ifdef to taste if some of the RL_STATE values aren't defined in the
readline version you're interested in.
Bash is not a good example to look at for this code, since it doesn't use
the callback interface.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU [email protected] http://cnswww.cns.cwru.edu/~chet/
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