Question

The below is from the official BOOST docs.
Why do I always get size of zero when calling region.get_size() ? What am I doing wrong?

int main(int argc, char *argv[])
{

  //Create a native windows shared memory object.
  windows_shared_memory shm (create_only, "MySharedMemory", read_write, 1000);

  //Map the whole shared memory in this process
  mapped_region region(shm, read_write);
  cout << "SIZE IS " << region.get_size() << endl;

return 0;
}

Answer 1

I think I got the answer:
From boost docs:

Native windows shared memory has also
another limitation: a process can open
and map the whole shared memory
created by another process but it
can’t know which is the size of that
memory. This limitation is imposed by
the Windows API so the user must
somehow transmit the size of the
segment to processes opening the
segment.