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MPI_Comm_set_name - Associates a name with a communicator.
#include <mpi.h>
int MPI_Comm_set_name(MPI_Comm comm, const char *comm_name)
INCLUDE ’mpif.h’
MPI_COMM_SET_NAME(COMM, COMM_NAME, IERROR)
INTEGER COMM, IERROR
CHARACTER*(*) COMM_NAME
#include <mpi.h>
void MPI::Comm::Set_name(const char* comm_name)
- comm
- Communicator whose identifier is to be set (handle).
- comm_name
- Character string to be used as the identifier
for the communicator (string).
- IERROR
- Fortran only: Error
status (integer).
MPI_Comm_set_name allows a user to associate
a name string with a communicator. The character string that is passed to
MPI_Comm_set_name is saved inside the MPI library (so it can be freed by
the caller immediately after the call, or allocated on the stack). Leading
spaces in name are significant, but trailing ones are not.
MPI_Comm_set_name
is a local (noncollective) operation, which affects only the name of the
communicator as seen in the process that made the MPI_Comm_set_name call.
There is no requirement that the same (or any) name be assigned to a communicator
in every process where it exists.
The length of the name that can be stored
is limited to the value of MPI_MAX_OBJECT_NAME in Fortran and MPI_MAX_OBJECT_NAME-1
in C and C++ (to allow for the null terminator). Attempts to set names longer
than this will result in truncation of the name. MPI_MAX_OBJECT_NAME must
have a value of at least 64.
Since MPI_Comm_set_name is provided
to help debug code, it is sensible to give the same name to a communicator
in all of the processes where it exists, to avoid confusion.
Regarding name
length, under circumstances of store exhaustion, an attempt to set a name
of any length could fail; therefore, the value of MPI_MAX_OBJECT_NAME should
be viewed only as a strict upper bound on the name length, not a guarantee
that setting names of less than this length will always succeed.
Almost
all MPI routines return an error value; C routines as the value of the
function and Fortran routines in the last argument. C++ functions do not
return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS,
then on error the C++ exception mechanism will be used to throw an MPI::Exception
object.
Before the error value is returned, the current MPI error handler
is called. By default, this error handler aborts the MPI job, except for
I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler;
the predefined error handler MPI_ERRORS_RETURN may be used to cause error
values to be returned. Note that MPI does not guarantee that an MPI program
can continue past an error.
MPI_Comm_get_name
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