From: "Deathifier" <storey AT tig DOT com DOT au>
Newsgroups: comp.os.msdos.djgpp
Subject: Some functions in Allegro I'm not sure of.
Date: Sat, 29 Aug 1998 16:38:36 +1000
Organization: The Internet Group Ltd
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Message-ID: <6s87mb$9hq$1@toto.tig.com.au>
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To: djgpp AT delorie DOT com
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Hello,
I'm trying to use the do_line() function in allegro, and I have a little
problem with the arguments to pass to it, here's what it has in the manual
(allegro.txt):

void do_line(BITMAP *bmp, int x1, y1, x2, y2, int d, void (*proc)());
   Calculates all the points along a line from point (x1, y1) to (x2, y2),
   calling the supplied function for each one. This will be passed a copy of
   the bmp parameter, the x and y position, and a copy of the d parameter,
   so it is suitable for use with putpixel().

I understand most of it, except for:
int d
void (*proc) ()

I have no idea what the d parameter is supposed to be, or what the *proc
function want's passed to it, I have tried using 0 and it doesn't work.  I'm
sure someone knows what values to pass or what these mean so if you do,
please help me out.

Cya,
David Storey