Subj : Re: Wayne King (disregard ealier question) BIOS interrupt
To   : borland.public.cpp.borlandcpp
From : "Gonzalo Núñez" <gnunezr@hotmail.com>
Date : Fri Aug 22 2003 09:46 am

Hi Rob.

    Here's a quick snip of code that gets the char and attribute from screen
at position 'x', 'y'.
Note that the function accesses directly the screen buffer. Note that the
text in the screen buffer
is ordered in two-byte pieces: one for the attribute, and one for the actual
text character. Be warned though,
I wrote this from memory and haven't tested, it can have errors!!!

unsigned int char_at( int x, int y )
{
    //
    // Set up a pointer to the screen buffer
    //
   char __far* scrSeg = (char*)0xB8000000L;
    //
    // Calculate the 'flat' position from x, y
    //
   int charPos = ( y * 80 ) + x;
    //
    //    Get the character
    //
   char textChar = scrSeg[ charPos ];
    //
    // Get the attribute
    //
   char attrChar = scrSeg[ charPos + 1 ];

    //
    // Pack them up
    //
   unsigned int result = ( attrChar << 8 ) | textChar;
    //
    // Return it
    //
   return result;
};

HTH

Gonzalo Núñez Riboni

.