plucky (3) MPI_Comm_set_name.openmpi.3.gz

SYNTAX

   C Syntax
          #include <mpi.h>

          int MPI_Comm_set_name(MPI_Comm comm, const char *comm_name)

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'
          MPI_COMM_SET_NAME(COMM, COMM_NAME, IERROR)
               INTEGER COMM, IERROR
               CHARACTER*(*) COMM_NAME

   Fortran 2008 Syntax
          USE mpi_f08
          MPI_Comm_set_name(comm, comm_name, ierror)
               TYPE(MPI_Comm), INTENT(IN) :: comm
               CHARACTER(LEN=*), INTENT(IN) :: comm_name
               INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT/OUTPUT PARAMETER

       • comm: Communicator whose identifier is to be set (handle).

INPUT PARAMETER

       • comm_name: Character string to be used as the identifier for the communicator (string).

OUTPUT PARAMETER

       • ierror: Fortran only: Error status (integer).

DESCRIPTION

       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  (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.

NOTES

       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.

ERRORS

       Almost  all  MPI  routines  return  an  error  value; C routines as the return result of the function and
       Fortran routines in the last argument.

       Before the error value is returned, the current MPI  error  handler  associated  with  the  communication
       object  (e.g.,  communicator, window, file) is called.  If no communication object is associated with the
       MPI call, then the call is considered attached to MPI_COMM_SELF and will call the  associated  MPI  error
       handler.   When   MPI_COMM_SELF   is   not  initialized  (i.e.,  before  MPI_Init/MPI_Init_thread,  after
       MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial  error  handler.
       The  initial  error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using
       the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info  key  to  MPI_Comm_spawn/‐
       MPI_Comm_spawn_multiple.   If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN
       error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is  called  for  all
       other MPI functions.

       Open MPI includes three predefined error handlers that can be used:

       • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

       • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When
         called on a communicator, it acts as if MPI_Abort was called on  that  communicator.  If  called  on  a
         window  or file, acts as if MPI_Abort was called on a communicator containing the group of processes in
         the corresponding window or file. If called on a session, aborts only the local process.

       • MPI_ERRORS_RETURN Returns an error code to the application.

       MPI applications can also implement their own error handlers by calling:

       • MPI_Comm_create_errhandler then MPI_Comm_set_errhandler

       • MPI_File_create_errhandler then MPI_File_set_errhandler

       • MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init

       • MPI_Win_create_errhandler then MPI_Win_set_errhandler

       Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.

       See the Error Handling section of the MPI-3.1 standard for more information.

       SEE ALSO:

          • MPI_Comm_get_name

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                              MPI_COMM_SET_NAME(3)