NAME¶
MPI_Comm_free_keyval - Frees attribute key for communicator cache
attribute.
SYNTAX¶
C Syntax¶
#include <mpi.h>
int MPI_Comm_free_keyval(int * comm_keyval)
Fortran Syntax¶
INCLUDE 'mpif.h'
MPI_COMM_FREE_KEYVAL( COMM_KEYVAL, IERROR)
INTEGER COMM_KEYVAL, IERROR
C++ Syntax¶
#include <mpi.h>
static void MPI::Comm::Free_keyval(int& comm_keyval)
- 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 erroneous 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 communicators).
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.