AW: global variables vs. custom properties
Tiemo Hollmann TB
toolbook at kestner.de
Fri Jan 16 10:30:54 CST 2009
Hi Rob, Bill and Jim,
It seems that the main difference in usage is, if you want / must
differentiate between different stacks and the purge of memory, when using
different stacks - as you have outlined.
Thank you for clarifying
> -----Ursprüngliche Nachricht-----
> Von: use-revolution-bounces at lists.runrev.com [mailto:use-revolution-
> bounces at lists.runrev.com] Im Auftrag von Jim Ault
> Gesendet: Freitag, 16. Januar 2009 16:41
> An: How to use Revolution
> Betreff: Re: global variables vs. custom properties
> There are also a drawbacks to gobals when designing reuseable functions
> If there is a global you like to use, say gRawTextString and
> gFormattedTextString, you could have situations where two different stacks
> you are developing are using the same names. This means that script
> debugging can be made more difficult if both stacks are open.
> One situation where this occurs is when you make your own Ask, Answer
> boxes and put them in to different stacks. Another is when you make
> stacks of your library routines.
> A specific example for me is the management of sockets in some of my
> networking apps. Things like StartUDP, StopUDP, gHostIP, gServerList,
> gFTPaddressWithLoginPswd, StartTcpIpSession, gIsRunning, gPacketToSend
> obviously not work properly if I have two or more communication stacks
> Custom properties are good in those situations because then either have
> specific, unambiguous locations or are assumed to be local (eg.
> on opencard
> set the cpsTimeData["cpFirstOpened"] of this card to the seconds
> Since globals are in memory space that is owned by Revolution and not the
> stack or library/plugin script that uses them, they don't die until you
> Revolution (large variable sizes remain in memory). A custom property is
> put into memory when the stack is opened, then purged when closed.
> A little more info for that might help.
> Jim Ault
> Las Vegas
> On 1/16/09 7:00 AM, "Rob Cozens" <rcozens at pon.net> wrote:
> > Hi Tiemo,:
> >> I know, that most people prefer custom properties, but is it just a
> >> of "school", or is there perhaps a difference in memory usage or other
> >> facts"?
> > Custom properties are stored within the stack file when it is saved,
> > whereas globals die when the Rev engine or your standalone quits.
> > So if your variables are non-persistant, then globals better fulfill
> > that function. If you have variables that are populated after
> > startup and don't need to persist after shut down, putting them in
> > custom properties simply increases the physical size of the stack
> > file for no useful purpose.
> > Rob Cozens CCW
> > Serendipity Software Company
> > "And I, which was two fooles, do so grow three;
> > Who are a little wise, the best fooles bee."
> > from "The Triple Foole" by John Donne (1572-1631)
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