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MPI_Comm_idup - Start the nonblocking duplication of an existing
communicator with all its cached information.
#include <mpi.h>
int MPI_Comm_idup(MPI_Comm comm, MPI_Comm *newcomm, MPI_Request *request)
USE MPI
! or the older form: INCLUDE ’mpif.h’
MPI_COMM_IDUP(COMM, NEWCOMM, REQUEST, IERROR)
INTEGER COMM, NEWCOMM, REQUEST, IERROR
USE mpi_f08
MPI_Comm_idup(comm, newcomm, request, ierror)
TYPE(MPI_Comm), INTENT(IN) :: comm
TYPE(MPI_Comm), INTENT(OUT) :: newcomm
TYPE(MPI_Request), INTENT(OUT) :: request
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
- comm
- Communicator (handle).
- newcomm
- Copy
of comm (handle).
- request
- Communication request (handle).
- IERROR
- Fortran
only: Error status (integer).
MPI_Comm_idup 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 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.
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 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.
Almost all MPI routines return an
error value; C routines as the value of the function and Fortran routines
in the last argument.
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.
MPI_Comm_dup MPI_Comm_dup_with_info
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