On Tue, May 14, 2013 at 11:05 AM, Oodini
Isn't that the point of your original question: you do not, in fact, know in advance the number of bytes you will need ?
I do know the full size, but I don't know the size of each vector.
You know the number of data items. You don't know the number of bytes. Hence your original question.
If you have a way to move forward without getting stuck on this issue, finish your code, evaluate its performance and then -- if necessary run a profiler to figure out what actually needs improving.
Unfortunately, I don't have access to a profiler.
I would look for one only if the program's performance is observed to be inadequate. I would spend effort on computing the correct initial size for the shared memory only if an observed performance problem is proven to be due to resizing shared memory. You're trying to solve a problem you don't even know you have. You are of course free to spend your time doing that; I'll stop trying to dissuade you.