18.2.72. MPI_Comm_set_attr

MPI_Comm_set_attr - Stores attribute value associated with a key.

18.2.72.1. SYNTAX

18.2.72.1.1. C Syntax

#include <mpi.h>

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

18.2.72.1.2. Fortran Syntax (see FORTRAN 77 NOTES)

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

18.2.72.1.3. 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

18.2.72.2. INPUT/OUTPUT PARAMETER

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

18.2.72.3. INPUT PARAMETERS

  • comm_keyval: Key value (integer).

  • attribute_val: Attribute value.

18.2.72.4. OUTPUT PARAMETER

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

18.2.72.5. 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.

18.2.72.6. FORTRAN 77 NOTES

The MPI standard prescribes portable Fortran syntax for the ATTRIBUTE_VAL argument only for Fortran 90. Sun FORTRAN 77 users may use the non-portable syntax

INTEGER*MPI_ADDRESS_KIND ATTRIBUTE_VAL

where MPI_ADDRESS_KIND is a constant defined in mpif.h and gives the length of the declared integer in bytes.

18.2.72.7. 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.

18.2.72.8. 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[_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.

In the sessions model, the error handler can be set during MPI_Session_init.

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.

Custom MPI error handlers can be created by calling: MPI_Comm_create_errhandler(3) MPI_File_create_errhandler(3) MPI_Session_create_errhandler(3) MPI_Win_create_errhandler(3)

Predefined and custom error handlers can be set by calling: MPI_Comm_set_errhandler(3) MPI_File_set_errhandler(3) MPI_Session_set_errhandler(3) MPI_Win_set_errhandler(3)

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 standard for more information.