Yup, it does. There's nothing in the standard that says it isn't
allowed to. Given the number of system/libc calls involved in doing
communication, pretty much every MPI function is going to change the
value of errno. If you expect otherwise, I'd modify your
application. Most cluster-based MPI implementations are going to
randomly change the errno on you.
Brian
On May 2, 2007, at 12:18 PM, Chudin, Eugene wrote:
I am trying to experiment with openmpi and following trivial code
(although runs) affects value of errno
#include <cerrno>
#include <mpi.h>
int main(int argc, char** argv)
{
int _procid, _np;
std::cout << "errno=\t" << errno << std::endl;
MPI_Init(&argc, &argv);
std::cout << "errno=\t" << errno << "\tafter MPI_Init()\t" <<
std::endl;
MPI_Comm_rank (MPI_COMM_WORLD, &_procid);
MPI_Comm_size (MPI_COMM_WORLD, &_np);
std::cout << "errno msg=\t" << strerror(errno) << "\tprocessor=
\t" << _procid << std::endl;
MPI_Finalize();
return 0;
}
Compiled with
mpiCC -Wall test.cpp -o test
Produces following output when run just on single processor using
mpirun -np 1 --prefix /toolbox/openmpi ./test
errno= 0
errno= 2 after MPI_Init()
errno msg= No such file or directory processor= 0
When run on two processors using
mpirun -np 2 --prefix /toolbox/openmpi ./test
errno= 0
errno= 0
errno= 11 after MPI_Init()
errno= 115 after MPI_Init()
errno msg= Operation now in progress processor= 0
errno msg= Resource temporarily unavailable
processor= 1
The output of ompi_info --all is attached
<<ompi_info.txt>>
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