From: "Michael Stewart" <mike AT reggin DOT freeserve DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
References: <ulmY4.563$x8 DOT 4314 AT nsw DOT nnrp DOT telstra DOT net>
Subject: Re: dj callbacks
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Date: Mon, 29 May 2000 19:51:33 +0100
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Paul Cechner <paul AT ibc DOT com DOT au DOT NOSPAM> wrote in message
news:ulmY4.563$x8 DOT 4314 AT nsw DOT nnrp DOT telstra DOT net...
> can you set up your own custom callbacks in dj?? and how???
Of course

> ie, can you (for instance) create a myObj::user_callback_handler() method
> which you initialise to be called when a certain trigger is thrown
elsewhere
> (ie, myBouncingObject::triggerThrower())? sort of reaction based
> programming....
Sure, see below.

> im not sure what terminology to use, so i hope you understand what im
> talking about.
I think you are refering to event driven programming.

> i want to use this to call a certain handler when some non-specific
trigger
> is thrown (ie, bringing up a menu when a any number of user actions is
> performed)

This is taken from Allegro

/* install_keyboard_hooks:
 *  You should only use this function if you *aren't* using the rest of the
 *  keyboard handler. It can be called in the place of install_keyboard(),
 *  and lets you provide callback routines to detect and read keypresses,
 *  which will be used by the main keypressed() and readkey() functions.
This
 *  can be useful if you want to use Allegro's GUI code with a custom
 *  keyboard handler, as it provides a way for the GUI to access keyboard
 *  input from your own code.
 */
void install_keyboard_hooks(int (*keypressed)(), int (*readkey)())
{
   keypressed_hook = keypressed;
   readkey_hook = readkey;
}

Mike