MPI_Comm_free_keyval(3)            Open MPI            MPI_Comm_free_keyval(3)



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)


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 explictly 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.




1.4.1                            Jan 14, 2010          MPI_Comm_free_keyval(3)
