Re: defer interrupt.

>From: uunet!rhi.hi.is!gaukur (Kristjan Gaukur Kristjansson) >Subject: Re: defer interrupt. >Date: 9 Nov 92 13:22:18 GMT >X-Informix-List-Id: <news.2090> >>Did you read pages S-29 - S-32 (in the English version, anyway) of the >>4GL 4.1 Supplement document? If so, what was unclear? >Yes I've read them, but maybe theres something wrong with my configuration. >In my test exemplar I'm interrupting a foreach loop thats fetching rows >and getting some of them into a report. All is revealed... The problem is that reports are pigs to break into, not that the defer interrupt stuff doesn't work particularly. Reports always have been neear enough impossible to interrupt, and they haven't changed recently. If you subject the program to blizzard of interrupts, then eventually, you usually manage to get a report to acknowledge that an interrupt has occurred. I haven't done exhaustive checking of SQL INTERRUPT ON but I think you will find it will work, except when there is a report in use. One day when I get some time, I'll try an track down what it is about reports that makes them immune from interrupt, but they always have been like that. >So is it maybe something wrong with my termcap? No, but an interrupt at an inconvenient moment may throw the key handling code out of kilter. That is the problem with interrupts... They're never expected. >Also one comment on the int_flag testing; if youre interrupting open, fetch, >close statements (with something in between) do you have to test the int_flag >after every statement (because you never know in loops where the ctrl-c will >hit)? You should check after the open (because if the staetment was interrupted, you don't have a properly open cursor with which to fetch data), after each fetch (because if the row wasn't fetched, you don't have any new data in your variables), and probably after the close (simply because you're about to go and do something with the fetched data, and ought to check that all was OK). You don't really need to check after each intermediate calculation; once per fetch loop is enough, nomally. (That assumes no nested SQL statements -- you should check after each database operation -- hence after open, fetch, close). Yours, Jonathan Leffler (johnl@obelix.informix.com) #include <disclaimer.h>