MPI_Comm_free_keyval(3) Open MPI MPI_Comm_free_keyval(3)
NAME
MPI_Comm_free_keyval - Frees attribute key for communicator cache at-
tribute.
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Comm_free_keyval(int *comm_keyval)
Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_COMM_FREE_KEYVAL(COMM_KEYVAL, IERROR)
INTEGER COMM_KEYVAL, IERROR
Fortran 2008 Syntax
USE mpi_f08
MPI_Comm_free_keyval(comm_keyval, ierror)
INTEGER, INTENT(INOUT) :: comm_keyval
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
C++ Syntax
#include <mpi.h>
static void MPI::Comm::Free_keyval(int& comm_keyval)
INPUT/OUTPUT PARAMETER
comm_keyval
OUTPUT PARAMETER
IERROR Fortran only: Error status (integer).
DESCRIPTION
MPI_Comm_free_keyval frees an extant attribute key. This function sets
the value of keyval to MPI_KEYVAL_INVALID. Note that it is not erro-
neous to free an attribute key that is in use, because the actual free
does not transpire until after all references (in other communicators
on the process) to the key have been freed. These references need to be
explicitly freed by the program, either via calls to
MPI_Comm_delete_attr that free one attribute instance, or by calls to
MPI_Comm_free that free all attribute instances associated with the
freed communicator.
This call is identical to the call MPI_Keyval_free but is needed to
match the communicator-specific creation function introduced in the
MPI-2 standard. The use of MPI_Keyval_free is deprecated.
NOTES
Key values are global (they can be used with any and all communica-
tors).
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_free_keyval(3)
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