18.2.67. MPI_Comm_idup_with_info

MPI_Comm_idup_with_info - Start the nonblocking duplication of an existing communicator with all its cached information.

18.2.67.1. SYNTAX

18.2.67.1.1. C Syntax

#include <mpi.h>

int MPI_Comm_idup_with_info(MPI_Comm comm, MPI_Info info, MPI_Comm *newcomm, MPI_Request *request)

18.2.67.1.2. Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_COMM_IDUP_WITH_INFO(COMM, INFO, NEWCOMM, REQUEST, IERROR)
    INTEGER    COMM, INFO, NEWCOMM, REQUEST, IERROR

18.2.67.1.3. Fortran 2008 Syntax

USE mpi_f08
MPI_Comm_idup_with_info(comm, info, newcomm, request, ierror)
    TYPE(MPI_Comm), INTENT(IN) :: comm
    TYPE(MPI_Info), INTENT(IN) :: info
    TYPE(MPI_Comm), INTENT(OUT) :: newcomm
    TYPE(MPI_Request), INTENT(OUT) :: request
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror

18.2.67.2. INPUT PARAMETER

  • comm: Communicator (handle). info Info object (handle).

18.2.67.3. OUTPUT PARAMETERS

  • newcomm: Copy of comm (handle).

  • request: Communication request (handle).

  • IERROR: Fortran only: Error status (integer).

18.2.67.4. DESCRIPTION

MPI_Comm_idup_with_info starts the nonblocking duplication of an existing communicator comm with associated key values. For each key value, the respective copy callback function determines the attribute value associated with this key in the new communicator; one particular action that a copy callback may take is to delete the attribute from the new communicator. Returns in newcomm a new communicator with the same group, any copied cached information, but a new context (see Section 5.7.1 of the MPI-1 Standard, “Functionality”). The communicator returned in newcomm will not be available until the request is complete. The hints provided by the supplied info argument are associated with the output communicator.

The completion of a communicator duplication request can be determined by calling any of MPI_Wait, MPI_Waitany, MPI_Test, or MPI_Testany with the request returned by this function.

18.2.67.5. NOTES

This operation is used to provide a parallel library call with a duplicate communication space that has the same properties as the original communicator. This includes any attributes (see below) and topologies (see Chapter 6, “Process Topologies,” in the MPI-1 Standard). This call is valid even if there are pending point-to-point communications involving the communicator comm. A typical call might involve an MPI_Comm_idup_with_info at the beginning of the parallel call, and an MPI_Comm_free of that duplicated communicator at the end of the call. Other models of communicator management are also possible.

This call applies to both intra- and intercommunicators.

Note that it is not defined by the MPI standard what happens if the attribute copy callback invokes other MPI functions. In Open MPI, it is not valid for attribute copy callbacks (or any of their children) to add or delete attributes on the same object on which the attribute copy callback is being invoked.

18.2.67.6. ERRORS

Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument.

Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. When MPI_COMM_SELF is not initialized (i.e., before MPI_INIT / MPI_INIT_THREAD, after MPI_FINALIZE, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling MPI_COMM_SET_ERRHANDLER on MPI_COMM_SELF when using the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_COMM_SPAWN[_MULTIPLE]. If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all other MPI functions.

In the sessions model, the error handler can be set during MPI_Session_init.

Open MPI includes three predefined error handlers that can be used:

MPI_ERRORS_ARE_FATAL: Causes the program to abort all connected MPI processes.
MPI_ERRORS_ABORT:     An error handler that can be invoked on a communicator,
                      window, file, or session. When called on a communicator, it
                      acts as if MPI_ABORT was called on that communicator. If
                      called on a window or file, acts as if MPI_ABORT was called
                      on a communicator containing the group of processes in the
                      corresponding window or file. If called on a session,
                      aborts only the local process.
MPI_ERRORS_RETURN:    Returns an error code to the application.

MPI applications can also implement their own error handlers.

Custom MPI error handlers can be created by calling: MPI_Comm_create_errhandler(3) MPI_File_create_errhandler(3) MPI_Session_create_errhandler(3) MPI_Win_create_errhandler(3)

Predefined and custom error handlers can be set by calling: MPI_Comm_set_errhandler(3) MPI_File_set_errhandler(3) MPI_Session_set_errhandler(3) MPI_Win_set_errhandler(3)

Note that MPI does not guarantee that an MPI program can continue past an error.

See the MPI man page for a full list of MPI error codes.

See the Error Handling section of the MPI-3 standard for more information.