MPI_Comm_set_attr(3)               Open MPI               MPI_Comm_set_attr(3)



NAME
       MPI_Comm_set_attr - Stores attribute value associated with a key.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Comm_set_attr(MPI_Comm comm, int comm_keyval, void *attribute_val)


Fortran Syntax (see FORTRAN 77 NOTES)
       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


C++ Syntax
       #include <mpi.h>
       void MPI::Comm::Set_attr(int comm_keyval, const void* attribute_val) const


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.


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.


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 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.




1.4.1                            Jan 14, 2010             MPI_Comm_set_attr(3)
