absolute address

[DosFreak]

in delphi you can use Ptr to an absolute address, can i do this in vc++.
in dos, i can use a dos font. i assume that if i save the dos font to
disk, then edit it, i have a new font. any copyright issues. or michael
mediford 20 years wrote editfont which did exactly that for dos. i was
trying to do the same for win32. but anyways, i was trying to get
biosinfo from the computer using vc++; seems like every computer is
different, it would be easier to use a pointer to point to it.

Marc...



--
DosFreak
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[Carl Daniel [VC++ MVP]]

Re: absolute address

DosFreak wrote:

in delphi you can use Ptr to an absolute address, can i do this in
vc++. in dos, i can use a dos font. i assume that if i save the dos
font to disk, then edit it, i have a new font. any copyright issues.
or michael mediford 20 years wrote editfont which did exactly that
for dos. i was trying to do the same for win32. but anyways, i was
trying to get biosinfo from the computer using vc++; seems like every
computer is different, it would be easier to use a pointer to point
to it.

There is no access to physical memory under Windows unless you write a
kernel device driver (and please, don't).

-cd

[Steve in Albury]

Re: absolute address

Are you trying to access memory in bios to get the font, or are you trying
to store a vriable at a particular memory location?

Steve

[Tamas Demjen]

Re: absolute address

DosFreak wrote:

in delphi you can use Ptr to an absolute address, can i do this in vc++.

The Delphi Ptr function converts an integer to a pointer. In C/C++, all
you need is a cast:

void* p = reinterpret_cas t<void*>(0xFFFF 5);

As others have said, this only works in DOS. You'll get an access
violation if you try to execute this in Win32.

Also, you should never use an integer to store a pointer, because that's
not going to work on x64, where int is 32-bit and void* is 64-bit. A lot
of Delphi code uses integers for HDC and HANDLE variables. There will be
major portability issues with those programs.

And finally, if you plan to distribute your product, you shouldn't steal
the font from the BIOS. There are plenty of monospace fonts out there,
and some of them were designed to look like a DOS terminal.

Tom

[Steve McKewen]

Re: absolute address

I have used copies of monospaced fonts read out of bioses in portable
equipment, but I have always ended up modifying the font at least a little
bit.
Nowadays I just write a font edit program and draw the font I want.
It ends up just being an array definition that contains all of the bytes
from the font.

If you want a font that is exactly the same as a bios font, but don't want
to actually use the bios font, then you will have to write your own font
draw functions anyway. I do that, but only in embedded stuff where I don't
have access to font systems that meet my needs.

Steve