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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_discon-nect MPI_Comm_disconnect
       nect or MPI_Comm_free will cause other references to the intercommunicator to  become  invalid  (dan-gling). (dangling).
       gling). 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




Open MPI 1.2                                   September 2006                  MPI_Comm_get_parent(3OpenMPI)