>>>> 4) Well, this sounds reasonable, but according to the MPI-1 standard
>>>> (see page 40 for non-blocking send/recv, a more detailed explanation in
>>>> page 30):
>>>> "A nonblocking send call indicates that the system may start copying
>>>> data out of the send buffer. The sender should */not access*/ any part
>>>> of the send buffer after a nonblocking send operation is called, until
>>>> the send completes."
>>>> So before calling MPI_Wait to complete an isend operation, any
>>>> access to
>>>> the send buffer is illegal. It might be a little strict, but we have to
>>>> do what the standard says.
>> This have been changed in the new version of the MPI standard (2.1).
>> There is no restriction anymore regarding the read operations on the
>> buffers used for non-blocking sends.
>Do you mean the next coming version of MPI standard? Because checking
>again standard 2.1 , I didn't see any changes of those paragraphs. See
>MPI Standard 2.1 (PDF version), page 52, and page 41.
The (non modifying) access to a send buffer was agreed for MPI Standard 2.2 not version 2.1 see the MPI 2.2 Wiki: