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Re: libpq/async notifications

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Igor Shevchenko <igor(at)carcass(dot)ath(dot)cx>
Cc: pgsql-interfaces(at)postgresql(dot)org
Subject: Re: libpq/async notifications
Date: 2003-10-14 17:18:29
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Lists: pgsql-interfaces
Igor Shevchenko <igor(at)carcass(dot)ath(dot)cx> writes:
> The idea behind this checking function is to separate the *checking* if 
> there's any notifications and actually *processing* them. I want to check 
> right after any transaction or any PQ* function which calls PQconsumeInput 
> and process notifications only once, after my app had returned to it's main 
> loop (I'm talking about GUI apps here). In Qt, for example, this is done by 
> creating a new QEvent and dispatching it via QApplication::postEvent(...), 
> which is quite an overhead; with just PQnotifies I have to do this all the 
> time.

How so?  Seems to me the check operation could read

	notify = PQnotifies(...);
	if (notify)
		make QEvent, put notify pointer in it, dispatch

The event handler then fetches the notify pointer from the QEvent
(and eventually frees it).

			regards, tom lane

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