osx man page for mpi_comm_get_parent

MPI_Comm_get_parent(3OpenMPI)											     MPI_Comm_get_parent(3OpenMPI)

NAME
       MPI_Comm_get_parent - Returns the parent intercommunicator of current spawned process.

SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Comm_get_parent(MPI_Comm *parent)

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_COMM_GET_PARENT(PARENT, IERROR)
	    INTEGER   PARENT, IERROR

C++ Syntax
       #include <mpi.h>
       static MPI::Intercomm MPI::Comm::Get_parent()

OUTPUT PARAMETERS
       parent	 The parent communicator (handle).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION
       If  a process was started with MPI_Comm_spawn or MPI_Comm_spawn_multiple, MPI_Comm_get_parent returns the "parent" intercommunicator of the
       current process. This parent intercommunicator is created implicitly inside of MPI_Init and is the same intercommunicator returned  by  the
       spawn call made in the parents.

       If the process was not spawned, MPI_Comm_get_parent returns MPI_COMM_NULL.

       After the parent communicator is freed or disconnected, MPI_Comm_get_parent returns MPI_COMM_NULL.

NOTES
       MPI_Comm_get_parent  returns a handle to a single intercommunicator. Calling MPI_Comm_get_parent a second time returns a handle to the same
       intercommunicator. Freeing the handle with MPI_Comm_disconnect or MPI_Comm_free will cause other references  to	the  intercommunicator	to
       become invalid (dangling). Note that calling MPI_Comm_free on the parent communicator is not useful.

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.

SEE ALSO
       MPI_Comm_spawn
       MPI_Comm_spawn_multiple

Open MPI 1.2							  September 2006				     MPI_Comm_get_parent(3OpenMPI)