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MPI_Comm_get_parent - Returns the parent intercommunicator of current spawned process.
#include <mpi.h> int MPI_Comm_get_parent(MPI_Comm *parent)
INCLUDE 'mpif.h' MPI_COMM_GET_PARENT(PARENT, IERROR) INTEGER PARENT, IERROR
#include <mpi.h> static MPI::Intercomm MPI::Comm::Get_parent()
parent The parent communicator (handle). IERROR Fortran only: Error status (integer).
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.
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.
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.