When I try to compile this:
#include <windows.h>
int _start(void){
unsigned char MyArray[4];
LPDWORD BytesWritten;
HANDLE hFile;
hFile=CreateFile("MyFile.dat",0xC0000000,0,0,2,0,0);
MyArray[0]=1;
MyArray[1]=2;
MyArray[2]=3;
MyArray[3]=4;
WriteFile(hFile,MyArray,4,BytesWritten,0);
CloseHandle(hFile);
}
I get a program that crashes when I run it. When I look at the dissassembly
in OllyDbg, it turns out that what's happening is that in the WriteFile
line of code, it's passing the value stored in BytesWritten, rather than
its memory address, even though BytesWritten has been declared with
LPDWORD, and even though LPDWORD has by defined (via typedef) as a pointer.
When a pointer type variable is passed it should be passing the memory
address, not the value stored there, but passing the value stored there is
EXACTLY what's happening. The ONLY time that the value stored at a pointer
should be passed is when you prefface that pointer with an asterisk. If I
have a variable declared like this:
LPDWORD MyPtr
Every time I use that pointer, including passing it as a parameter in a
function as just MyPtr, it SHOULD be passing the memory address, not the
value stored there. The ONLY time that it should it should be using the
value stored in a pointer-type variable there is if I am using an astrisk
with it, like this:
*MyPtr
As you can see from the above code sample, my pointer-type variable is
being passed in such a way that it should be passing the ADDRESS to the
function, NOT passing the value, yet passing the value is exactly what's
happening, as I can tell by running the program in a debugger.
This is a MAJOR glitch. It's what I call a "show stopper" glitch. It is
significant enough that it will prevent you from from writing any decent
program in TCC. I only wish the author of this software didn't stop
updating it back in 2013. There's still quite a few bugs that are still NOT
FIXED.