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From: vail@tegra.COM (Johnathan Vail)
Newsgroups: comp.lang.c++
Subject: Bug or drain bamage?
Message-ID: <2171@atlas.tegra.COM>
Date: 15 Mar 91 20:18:45 GMT
Organization: Tegra-Varityper, Inc., Billerica, MA
Lines: 73



Is this a bug with Turbo c++?  I am hoping it is just a difference
between C and C++ that I am not aware of yet.  This part of the
program is still straight C.

Given the following code, I want to call the function from the structure bp->
and pass to it the address of the structure (the pointer bp).  Tracing
shows that it gets there but bp is not being passed.  i am thinking
now that maybe the argument bp was already pushed (the optimizer moved
it up a few lines or something) but the called function does not have
it properly.

(One more data: this used to work "old" tc  before I started to convert
 the program to c++)

________________

THE C:

/*
 *  If there is a callback then call it with the ptr to the button
 */
if (bp->down_callback) {
	(bp->down_callback)(bp);
}
return;

________________

THE CPU INSTRUCTIONS:

CPU 80286

#BUTTON#37:  if (bp->down_callback) {
  cs:0796 837C0F00       cmp    word ptr [si+0F],0000
  cs:079A 7403           je     #BUTTON#40 (079F)

#BUTTON#38:  (bp->down_callback)(bp);
  cs:079C FF540F         call   [si+0F]

#BUTTON#40:  return;
  cs:079F EB07           jmp    #BUTTON#44 (07A8)
#BUTTON#42:  bp=bp->next;
  cs:07A1 8B7413         mov    si,[si+13]

________________

THE typdef USED AND THE DECLARATION OF THE FIELD:

typedef void (Function(ButtonPtr));

	Function *down_callback;

________________

AND THE CALLED FUNCTION:

void reverse_icon(ButtonPtr b)


Thanks for any help.

jv


"Love is a snowmobile racing across the tundra and then suddenly it flips
 over, pinning you underneath.  At night, the ice weasels come."
--Matt Groening
 _____
|     | Johnathan Vail | n1dxg@tegra.com
|Tegra| (508) 663-7435 | N1DXG@448.625-(WorldNet)
 -----  jv@n1dxg.ampr.org {...sun!sunne ..uunet}!tegra!vail