osx man page for mpi_comm_free_keyval

MPI_Comm_free_keyval(3OpenMPI)											    MPI_Comm_free_keyval(3OpenMPI)

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 communi-
       cators  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++ 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.

Open MPI 1.2							  September 2006				    MPI_Comm_free_keyval(3OpenMPI)