#include <stdio.h>
#include <conio.h>
#include <dos.h>

#define IGNORE  0
#define RETRY   1
#define ABORT   2

int buf[500];

/*
define the error messages for trapping disk problems
*/
static char *err_msg[] = {
    "write protect",
    "unknown unit",
    "drive not ready",
    "unknown command",
    "data error (CRC)",
    "bad request",
    "seek error",
    "unknown media type",
    "sector not found",
    "printer out of paper",
    "write fault",
    "read fault",
    "general failure",
    "reserved",
    "reserved",
    "invalid disk change"
};

error_win(char *msg)
{
   int retval;

   cputs(msg);

/*
prompt for user to press a key to abort, retry, ignore
*/
   while(1)
   {
       retval= getch();
       if (retval == 'a' || retval == 'A')
       {
           retval = ABORT;
           break;
       }
       if (retval == 'r' || retval == 'R')
       {
           retval = RETRY;
           break;
       }
       if (retval == 'i' || retval == 'I')
       {
           retval = IGNORE;
           break;
       }
   }

   return(retval);
}

/*
pragma warn -par reduces warnings which occur
due to the non use of the parameters errval,
bp and si to the handler.
*/
#pragma warn -par

int handler(int errval,int ax,int bp,int si)
{
   static char msg[80];
   unsigned di;
   int drive, errorno;

   di= _DI;													// if this is not a disk error then it was
																// another device having trouble
   if (ax < 0)
    {
      error_win("Device error");				      // report the error
      hardretn(ABORT);									// and return to the program directly requesting abort
    }
   drive = ax & 0x00FF;									// otherwise it was a disk error
   errorno = di & 0x00FF;								// report which error it was
   sprintf(msg, "Error: %s on drive %c\r\nA)bort, R)etry, I)gnore: ",
           err_msg[errorno], 'A' + drive);
   hardresume(error_win(msg));						// return to the program via dos interrupt 0x23 with abort, retry,
																// or ignore as input by the user.
   return ABORT;
 }
#pragma warn +par

void main(void)
 {
// install the handler on the hardware problem interrupt
   harderr(handler);
   clrscr();
   printf("Make sure there is no disk in drive A:\n");
   printf("Press any key ....\n");
   getch();
   printf("Trying to access drive A:\n");
   printf("fopen returned %p\n",fopen("A:temp.dat", "w"));
 }