plucky (3) MPI_Comm_set_attr.openmpi.3.gz

SYNTAX

   C Syntax
          #include <mpi.h>

          int MPI_Comm_set_attr(MPI_Comm comm, int comm_keyval, void *attribute_val)

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'
          MPI_COMM_SET_ATTR(COMM, COMM_KEYVAL, ATTRIBUTE_VAL, IERROR)
               INTEGER COMM, COMM_KEYVAL, IERROR
               INTEGER(KIND=MPI_ADDRESS_KIND) ATTRIBUTE_VAL

   Fortran 2008 Syntax
          USE mpi_f08
          MPI_Comm_set_attr(comm, comm_keyval, attribute_val, ierror)
               TYPE(MPI_Comm), INTENT(IN) :: comm
               INTEGER, INTENT(IN) :: comm_keyval
               INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: attribute_val
               INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT/OUTPUT PARAMETER

       • comm: Communicator from which attribute will be attached (handle).

INPUT PARAMETERS

       • comm_keyval: Key value (integer).

       • attribute_val: Attribute value.

OUTPUT PARAMETER

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

DESCRIPTION

       MPI_Comm_set_attr  stores  the  stipulated  attribute  value  attribute_val  for  subsequent retrieval by
       MPI_Comm_get_attr. If the value is already present, then the outcome is as  if  MPI_Comm_delete_attr  was
       first  called  to delete the previous value (and the callback function delete_fn was executed), and a new
       value was next stored. The call is erroneous if there is no key with  value  comm_keyval;  in  particular
       MPI_KEYVAL_INVALID  is  an  erroneous key value. The call will fail if the delete_fn function returned an
       error code other than MPI_SUCCESS.

       This function replaces MPI_Attr_put, the use of which is deprecated. The  C  binding  is  identical.  The
       Fortran binding differs in that attribute_val is an address-sized integer.

NOTES

       Values  of  the  permanent  attributes  MPI_TAG_UB,  MPI_HOST, MPI_IO, and MPI_WTIME_IS_GLOBAL may not be
       changed.

       The type of the attribute value depends on whether C or Fortran is being used. In C, an  attribute  value
       is  a  pointer (void *); in Fortran, it is a single, address-size integer system for which a pointer does
       not fit in an integer.

       If an attribute is already present, the delete function (specified  when  the  corresponding  keyval  was
       created) will be called.

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.

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                              MPI_COMM_SET_ATTR(3)