MPI_Comm_get_attr(3OpenMPI)											       MPI_Comm_get_attr(3OpenMPI)

NAME

       MPI_Comm_get_attr - Retrieves attribute value by key.

SYNTAX

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

Fortran Syntax (see FORTRAN 77 NOTES)
       INCLUDE 'mpif.h'
       MPI_COMM_GET_ATTR(COMM, COMM_KEYVAL, ATTRIBUTE_VAL, IERROR)
	    INTEGER   COMM, COMM_KEYVAL, IERROR
	    INTEGER(KIND=MPI_ADDRESS_KIND) ATTRIBUTE_VAL
	    LOGICAL FLAG

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

INPUT PARAMETERS

       comm	 Communicator to which the attribute is attached (handle).

       comm_keyval
		 Key value (integer).

OUTPUT PARAMETER

       attribute_val
		 Attribute value, unless flag = false.

       flag	 False if no attribute is associated with the key (logical).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       MPI_Comm_get_attr  retrieves  an attribute value by key. The call is erroneous if there is no key with value keyval. On the other hand, the
       call is correct if the key value exists, but no attribute is attached on comm for that key; in that case, the call returns flag = false. In
       particular, MPI_KEYVAL_INVALID is an erroneous key value.

       This  function  replaces  MPI_Attr_get,	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.

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++ func-
       tions 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.

Open MPI 1.2							  September 2006				       MPI_Comm_get_attr(3OpenMPI)