Question

My basic task is to get a subset of an buffer-array into another buffer array:

char buffer[max_len];

unit8 *pDestBuffer;

I used this code, because I would like to stay in ANSI-C:

memcpy(pDestBuffer, buffer, 4);

However – something must be wrong, because I don’t get my result as I expect to. Because, when I debug buffer, I see all the slots of the array – when I do this with pDestBuffer, I get only one Item – which I can change however, with something like memset(pDestBuffer,1,4)

pDestBuffer is part of a structure, and the only other reference to it, besides the definition above, was were these lines:

requiredMemory = sizeof(Structure) + bufferSize;
pStructure = (Structure *)HostMalloc(requiredMemory);
pStructure->pDestBuffer = ((uint8 *)pStructure)+sizeof(Sturcture);

I know, this might be rather a basic task, and I am working on this myself, but please, if there is a “best-practice” for this or you know a solution, please share it with me.

As a twist, I would really like to know, if there might be an improved way for this, using the boost-libraries, which I do use anyways for other problems.

Answer 1

Your code is working. Just because your debugger cannot see the data doesn’t mean it’s not there. What’s happening is that your code says uint8_t * pDestbuffer; so your debugger thinks that pDestBuffer is just a pointer to a single byte, so that’s what it shows. You know however that it’s actually a pointer to an array.

There may be some way of telling your debugger that this is an array so you can see all the data. For instance, one debugger I know would let you type in pStructure->pDestBuffer,4 to say show me four bytes not just one.