OpenEuphoria

Re: Callbacks

• Posted by Greg Harris <blackdog at CDC.NET> Sep 13, 1999
• 415 views

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
>