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From: mouse@lightning.mcrcim.mcgill.EDU
Newsgroups: comp.windows.x
Subject: Re:  freeing resources
Message-ID: <9102271436.AA01369@lightning.McRCIM.McGill.EDU>
Date: 27 Feb 91 14:36:28 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 46

> Lately I have been wondering if there are any advantages to freeing
> resources when you diconnect from the X server.  I mean, before I
> make a call to XCloseDisplay() I usually make calls to XFreeThis and
> XFreeThat with a liberal dose of XDestroy all around.

It makes it easier to lift your code and use it as part of something
larger.  As far as I can think of at the moment that's the only
benefit.  There is also an argument on the other side: just closing the
display is quick compared to making slew of FreeFoo requests and *then*
closing the display.

I typically just exit() and forget about the XCloseDisplay().  About
all it would buy me is the final XSync(), and I don't care about
asynchronous errors 'cuz I'm going away anyway and wouldn't be around
to report them!  And I don't care about the final XFlush() 'cuz I'm
dying on a received event and don't have anything to do except possibly
draw in my own window, which is about to go away.

> I know that the server will do all of this for me in most cases,

All cases, unless you've set your close-down mode (XSetCloseDownMode)
to RetainPermanent or RetainTemporary, in which case none of them are
destroyed automatically.

Modulo bugs, of course.

Quoting from the protocol document:

	At connection close, [...].  If close-down mode (see
	SetCloseDownMode request) is RetainPermanent or
	RetainTemporary, then all resources [...] allocated by the
	client are marked as permanent or temporary, respectively
	[...].  If the mode is Destroy, all of the client's resources
	are destroyed.
	
	When a client's resources are destroyed, [...save-set
	processing...].  After save-set processing, all windows created
	by the client are destroyed.  For each nonwindow resource
	created by the client, the appropriate Free request is
	performed.  All colors and colormap entries allocated by the
	client are freed.

					der Mouse

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