[mpich-discuss] MPI_Get on the same memory location

[Nick Radcliffe]

> MPIR_Localcopy(357): memcpy arguments alias each other, dst=0x19a5f40
src=0x19a5f40 len=4

It looks like memcpy is doing a check to make sure the source and destination buffers don't overlap. This seems like a bug to me -- when doing an MPI_Get from a buffer to itself, the implementation should probably just do nothing and return.

-Nick

________________________________________
From: alessandro.fanfarillo at gmail.com [alessandro.fanfarillo at gmail.com] on behalf of Alessandro Fanfarillo [fanfarillo at ing.uniroma2.it]
Sent: Thursday, August 21, 2014 5:25 PM
To: discuss at mpich.org
Subject: [mpich-discuss] MPI_Get on the same memory location

Dear all,

I'm having the following error:

Fatal error in MPI_Get: Internal MPI error!, error stack:
MPI_Get(156).......: MPI_Get(origin_addr=0x19a5f40, origin_count=4,
MPI_BYTE, target_rank=0, target_disp=0, target_count=4, MPI_BYTE,
win=0xa0000000) failed
MPIDI_Get(247).....:
MPIR_Localcopy(357): memcpy arguments alias each other, dst=0x19a5f40
src=0x19a5f40 len=4

if I try to execute MPI_Get on the same memory location on a shared
memory machine (my laptop).

I cannot find anything in the standard that denies it for the one-sided.

Running with OpenMPI everything works fine.

Is it a bug or I missed something in the standard?

Thanks.

Alessandro

--

Alessandro Fanfarillo
Dip. di Ingegneria Civile ed Ingegneria Informatica
Università di Roma "Tor Vergata"
NCAR Office: +1 (303) 497-2442
Tel: +39-06-7259 7719
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