MPI_Comm_get_attr(3) Open MPI MPI_Comm_get_attr(3)
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)
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_COMM_GET_ATTR(COMM, COMM_KEYVAL, ATTRIBUTE_VAL, FLAG, IERROR)
INTEGER COMM, COMM_KEYVAL, IERROR
INTEGER(KIND=MPI_ADDRESS_KIND) ATTRIBUTE_VAL
LOGICAL FLAG
Fortran 2008 Syntax
USE mpi_f08
MPI_Comm_get_attr(comm, comm_keyval, attribute_val, flag, ierror)
TYPE(MPI_Comm), INTENT(IN) :: comm
INTEGER, INTENT(IN) :: comm_keyval
INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(OUT) :: attribute_val
LOGICAL, INTENT(OUT) :: flag
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
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 er-
roneous 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 attri-
bute_val is an address-sized integer.
FORTRAN 77 NOTES
The MPI standard prescribes portable Fortran syntax for the ATTRI-
BUTE_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.
4.1.2 Nov 24, 2021 MPI_Comm_get_attr(3)
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