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