oracular (3) MPI_Comm_free_keyval.openmpi.3.gz

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

       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 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.