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self-modifying code API

Posted on 1998-11-30
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Last Modified: 2010-04-04
I am trying to make "self-modifying" code, like the following example:

procedure TForm1.Button1Click(Sender: TObject);
var
P: ^Byte;
begin
     P := Addr(TForm1.Button1Click);
     ShowMessage('The address is: ' + IntToHex(Integer(P), 8));
     P^ := 0;    //   <---- Access Violation occurs here
     ShowMessage('Done!');
end;


but the system reports:

Access violation at address 0042BBCA in module 'Project1.exe'
Write of address 0042BB6c

which is understandable, since this is not .DATA segment, but .CODE

What is API(s)  for "unlocking" the CODE segment?
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Comment
Question by:yuhoo
1 Comment
 
LVL 20

Accepted Solution

by:
Madshi earned 200 total points
ID: 1348706
Look at VirtualProtect(Ex)...

Regards, Madshi.
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