How to initialize a char bytecode array on the heap in C++

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Hi. I am trying to get a large char array allocated from the heap. From the stack, this code:

C++

unsigned char buf[] = { 0x48, 0x33, 0x65, .... };

works fine but if the bytecode is over 200,000, WriteProcessMemory will NOT copy more than 12224 bytes! There is indeed some kind of limit with these buffer arrays, Ive tested this too many times. So then I tried to get it from the heap but can't actually figure out how to initialize it

C++

unsigned char *buf = new unsigned char[256000];
buf = { 0x48, 0x33, 0x65, .... };

^ this throws an error buf does not name a type.

How can I simply declare an unsigned char array and initialize it at the same time. I've tried a one liner together, doesn't work. C++ seems like a very specific programming language. It's nothing compared to C. Thank you.

What I have tried:

tried to initialize it on the heap

Posted 17-May-22 7:07am

Franz Schweizer

Updated 19-May-22 20:08pm

v5

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0x01AA 17-May-22 14:30pm

You like to tell that you list here buf = { 0x48, 0x33, 0x65, .... }; 256'000 characters in your cpp file?
In case yes, I suggest it to put that into a binary resource and load it from there.

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Rick York · Answer 1 · 2022-05-17T10:11:00

I am not sure why you are having a problem and I am fairly certain that there is no limit of 12224 bytes. I have a structure initialized by including a header file that is over 512KB and it compiles just fine. In my case it is a structure with three members and there are almost 4700 of them and one is a text string of varying length. FWIW, it is a table of windows error codes and message strings. As I mentioned I put them all in a file that is included by the code. The code that does that looks like this :

C++

werrmsg Messages[] =
{
    #include "WindowsErrorList.h"
};

My point is this is a statically defined structure with a lot of members and over 512KB of data. If you take that approach with your data I think you can make it work. I wrapped mine in a local namespace and I recommend that for your data but it is not required.

You could do something like this :

C++

namespace // the anonymous namespace
{
const UCHAR BufferData[] =
{
#include "BufferData.h"
};

} // namespace

and the file with the data could look like this :

C++

  0x48
, 0x33
, 0x67
// and so on