1. Callbacks
Hi Eutopia
I want to ask if the callback mechanism has to do with the
non-multithreading (or, maybe more correctly, the interprented) nature
of Euphoria. I have problems with a program with more than one
callback functions (the one, of course, is the main WndProc) which
seem to be called asynchrounsly.
Thanks
-George-
---------
EUZE{I}N
2. Callbacks
- Posted by Greg Harris <blackdog at CDC.NET>
Sep 12, 1999
-
Last edited Sep 13, 1999
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Hi All,
I'm working with dynamic subclassing and would like to know if when I am =
done with a previously defined callback can I use free() to clear it? Or =
will this do bad things.. I have already restored the old callback using =
SetWindowLong.
Any help would be appreciated!
Thanks,
Greg Harris
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<HTML><HEAD>
<META content=3D"text/html; charset=3Diso-8859-1" =
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<DIV><FONT size=3D2>Hi All,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=3D2>I'm working with dynamic subclassing and would like =
to know if=20
when I am done with a previously defined callback can I use free() to =
clear it?=20
Or will this do bad things.. I have already restored the old callback =
using=20
SetWindowLong.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=3D2>Any help would be appreciated!</FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=3D2>Thanks,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=3D2>Greg Harris</FONT></DIV>
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3. Re: Callbacks
- Posted by Robert Craig <rds at ATTCANADA.NET>
Sep 13, 1999
-
Last edited Sep 14, 1999
Greg Harris writes:
> I'm working with dynamic subclassing and would like to
> know if when I am done with a previously defined callback
> can I use free() to clear it? Or will this do bad things.. I have
> already restored the old callback using SetWindowLong.
free() can only be used to free a block of memory allocated
using allocate() or allocate_string(). If you try to free a
callback address, it might work most of the time, but don't
count on it always working.
callback() returns an address that you can use to call
a Euphoria routine from Windows or a C routine.
callback() allocates some memory for this, but it's a small
amount - about 80 bytes. Once you get a callback address
for a Euphoria routine, you can use it for the rest of the program.
I don't see much need for freeing this space. If you have
a hundred different callback routines, you only need 8000 bytes.
Regards,
Rob Craig
Rapid Deployment Software
http://www.RapidEuphoria.com
4. Re: Callbacks
- Posted by Greg Harris <blackdog at CDC.NET>
Sep 13, 1999
-
Last edited Sep 14, 1999
Robert,
Thanks for the information!
Regards,
Greg Harris
----- Original Message -----
From: Robert Craig <rds at ATTCANADA.NET>
To: <EUPHORIA at LISTSERV.MUOHIO.EDU>
Sent: Monday, September 13, 1999 9:52 PM
Subject: Re: Callbacks
> Greg Harris writes:
> > I'm working with dynamic subclassing and would like to
> > know if when I am done with a previously defined callback
> > can I use free() to clear it? Or will this do bad things.. I have
> > already restored the old callback using SetWindowLong.
>
> free() can only be used to free a block of memory allocated
> using allocate() or allocate_string(). If you try to free a
> callback address, it might work most of the time, but don't
> count on it always working.
>
> callback() returns an address that you can use to call
> a Euphoria routine from Windows or a C routine.
> callback() allocates some memory for this, but it's a small
> amount - about 80 bytes. Once you get a callback address
> for a Euphoria routine, you can use it for the rest of the program.
> I don't see much need for freeing this space. If you have
> a hundred different callback routines, you only need 8000 bytes.
>
> Regards,
> Rob Craig
> Rapid Deployment Software
> http://www.RapidEuphoria.com
>
