Writing char to adress

[XxharCs]

Hey, after a long time i started again with memory editing and i stucked at one point.

I dont wanna use WriteProcessMemory to write new chars/int´s and so on, to an address. (from a dll)

Normally with a number it works..
example:

DWORD BasePointer = 0x006FA108;
...
...
DWORD dwBasePointer = *(DWORD*)BasePointer;
*(DWORD*)(dwBasePointer) = 2;

but when i try to do the same, but with a char, it doesn´t work:

char* helVal= "Hello";
LPVOID dwBasePointer = (DWORD*)0x006FA108;

dwBasePointer = helVal;

am i forgetting something or what?
if this method doesn´t work (with chars), then i am going to work with WriteProcessMemory to write chars..

Thanks!

[kingdeking]

memcpy, strcpy

[XxharCs]

ah thanks, forgot that there is also a memcpy

can be closed

[MrSm!th]

You don't understand pointers correctly, I think.

//x86 compatible only, haters gonna hate

DWORD *dwPtr = (DWORD *)0xDEADBEEF;   //writing 0xDEADBEEF into the variable dwPtr (or: at address of dwPtr) 
*dwPtr = 5;    //writing 5 at address 0xDEADBEEF

const char *cstrVal = "C-Style-String";

const char *strPtr = (const char *)0xDEADBEEF;   //writing 0xDEADBEEF into the variable strPtr (or: at address of strPtr)

strPtr = cstrVal;    //writing the address of "C-Style-String" into the variable strPtr (or: at the address of strPtr) - NOT writing the content ("C-Style-String") at the address saved in strPtr (0xDEADBEEF)

A C-Style string is simply a pointer to a char-Array or rather to the first element of that array. The pointer works exactly the same way an int* does.

char *strPtr = (char *)0xDEADBEEF; //now leaving out const to make the ptr writeable
*strPtr = *cstrVal; //writing the 'C', the first character of the string pointed to by cstrVal (because it is actually a pointer to that one char) at 0xDEADBEEF

You wouldn't think that

DWORD vals[] = { 1, 2, 3 };

dwPtr = vals;
//or
*dwPtr = *vals;

would copy the whole DWORD array either, would you?
Of course not. You need a loop for that. Luckily, there is already a well-optimized solution for that provided by the standard library: memcpy/strcpy/strcpy_s.


Btw.

char *helVal = "Hello";

Your compiler should complain about that line, because you are implicitly converting a const char* into a non-const char* there, which is not possible.


Anyway, #closed