C++ boost : windows shared memory get_size() returns zero

Question

以下内容来自官方 BOOST 文档。为什么在调用 region.get_size() 时我的大小总是为零？我做错了什么？

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

我想我得到了答案:来自 boost 文档:

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.