From: Endlisnis <s257m AT unb DOT ca>
Newsgroups: comp.os.msdos.djgpp
Subject: Mouse Handling
Date: Sun, 5 Jul 1998 12:59:42 -0300
Organization: University of New Brunswick
Lines: 71
Message-ID: <Pine.SOL.3.96.980705120455.14877A-100000@sol.sun.csd.unb.ca>
Reply-To: Endlisnis <s257m AT unb DOT ca>
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To: djgpp AT delorie DOT com
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	I tried to set up one of the examples shown in the FAQ to have a
function of mine called every time a mouse event occurs.  My function
doesn't contain any code, it is just blank.  Yet anytime the mouse moves,
the system crashes.  Can anyone tell me what I'm doing wrong?  I even
tried locking the memory used by the function to no avail.  Here is the
code.

//----------------------------------------------------------------
#include <iostream.h>
#include <dpmi.h>
#include <go32.h>


static __dpmi_regs        callback_regs;
static _go32_dpmi_seginfo callback_info;

volatile struct {
 int x,y,b;
 } Mouse;

int InstallHandler (unsigned mask, void (*func)(__dpmi_regs *), int Size)
{
 __dpmi_regs r;

 callback_info.pm_offset = (long)func;
 if (_go32_dpmi_allocate_real_mode_callback_retf(&callback_info,
&callback_regs))
  return -1;  /* failure */
 r.x.ax = 0xc;
 r.x.cx = mask;
 __dpmi_int (0x33, &r);
 _go32_dpmi_lock_data(func,Size);
 return (r.x.flags & 1) ? -1 : 0;
}

void MouseHandle(__dpmi_regs* Regs)
{
 //Mouse.x = (*Regs).x.cx;
 //Mouse.y = (*Regs).x.dx;
 //Mouse.b = (*Regs).x.bx;
 }

char InitMouse()
{
 __dpmi_regs Regs;
 //memset(&Regs, 0, sizeof(Regs));
 Regs.x.ax=0;
 __dpmi_int(0x33, &Regs);
 return Regs.x.ax;
 }


void main()
{
 if(!InitMouse()) {
  cout << "No Driver present!";
  return;  }
 if(InstallHandler(0x1F, MouseHandle, 
                   (unsigned)main-(unsigned)MouseHandle)==-1)
{
  cout << "Didn't work!";
  return;  }
 while(Mouse.x!=80)
  cout << Mouse.x << "," << Mouse.y << "," << Mouse.b << "\r";
 }



	Endlisnis
[I have a pyramid of wingyness]