Re: [Boost-users] [MPI] lifetime of data sent through communicator::isend()

Hi Heiko and Noel, On Sun, Nov 21, 2010 at 9:27 AM, Heiko Bauke wrote:

Riccardo Murri wrote:

...

I'm using mpi::communicator::isend where the payload data comes from a pointer (e.g., "req = comm_.isend(dest, tag. *data)"). When am I free to "delete" the pointer?  Immediately after isend() returns?  Or should I wait until the request is completed?

yes, you have to wait before you can free your memory. See http://www.mpi-forum.org/docs/mpi22-report/node57.htm and the following pages.

Thanks for the answers. However, I think I didn't make myself clear: I know what I should do with the C-level MPI_ISend() calls, I'm not sure what I can do after an Boost.MPI's communicator::isend(). My reading of the docs is that Boost.MPI creates an instance of boost::mpi::packed_oarchive archive and sends *that* one with MPI_ISend(). So the question is: can I "delete data;" immediately after I do "communicator::isend(..., *data);", or does the Boost.MPI archive hold a reference to the "*data" buffer? In other words, does Boost.MPI *copy* data into the archive or does it just reference it somehow? Thanks again and best regards, Riccardo