Re: Question about Ctrl-C and less

This has been saved for the 8.2 release:
http://momjian.postgresql.org/cgi-bin/pgpatches_hold

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Martijn van Oosterhout wrote:
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> On Sun, Oct 16, 2005 at 04:06:04PM -0400, Andrew Dunstan wrote:
> > Martin,
> > 
> > Let's see the patch. I assume it should be fairly small. If we could get 
> > it in early in the 8.2 cycle we would have plenty of time to bang on it. 
> > In principle this sounds reasonable to me, but psql can be broken quite 
> > easily - I know as I've done it a couple of times ;-)
> 
> Very well, patch attached. It's quite simple actually. However, there
> seems to be some push back from people suggesting that jumping back to
> the main loop before the pager has quit is not buggy behaviour.
> Assuming that a ^C will kill the pager is just folly.
> 
> Tom asked if we should be blocking SIGQUIT and SIGHUP too. Standard
> procedure for spawning external interactive processes includes blocking
> SIGQUIT too (see system() manpage). Logically speaking, when the user
> sends an interrupt from the keyboard they expect to interrupt the
> currently active *interaxtive* process. Hence, once psql has spawned
> the pager, it should ignore such interrupts until control is returned
> (after pclose). So yes, I would suggest blocking SIGQUIT also, if only
> to prevent terminal corruption problems. Interactive programs like less
> trap SIGQUIT to restore the terminal settings on exit, but the exit
> anyway.
> 
> SIGHUP is different. It is sent by the system, not the user, indicating
> the terminal has disconnected. psql is not a daemon expecting to
> survive that and hence should quit as normal, along with all other
> processes on that terminal.
> 
> If this isn't going to make 8.1 anyway I'd probably go for a patch that
> got rid of the longjmp altogether (if people will accept that), fixing
> the memory leaks at the same time. At the moment I'm just looking for a
> concensus that it's a problem to be solved.
> 
> Have a nice day,
> -- 
> Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> > tool for doing 5% of the work and then sitting around waiting for someone
> > else to do the other 95% so you can sue them.

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