MPI_Comm_get_parent(3)             Open MPI             MPI_Comm_get_parent(3)



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++
       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.


SEE ALSO
       MPI_Comm_spawn
       MPI_Comm_spawn_multiple




1.4.1                            Jan 14, 2010           MPI_Comm_get_parent(3)
