[97] | 1 | .\"Copyright 2006-2008 Sun Microsystems, Inc. |
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| 2 | .\" Copyright (c) 1996 Thinking Machines Corporation |
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| 3 | .TH MPI_Comm_dup 3 "Dec 08, 2009" "1.4" "Open MPI" |
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| 4 | .SH NAME |
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| 5 | \fBMPI_Comm_dup \fP \- Duplicates an existing communicator with all its cached information. |
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| 6 | |
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| 7 | .SH SYNTAX |
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| 8 | .ft R |
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| 9 | .SH C Syntax |
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| 10 | .nf |
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| 11 | #include <mpi.h> |
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| 12 | int MPI_Comm_dup(MPI_Comm \fIcomm\fP, MPI_Comm\fI *newcomm\fP) |
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| 13 | |
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| 14 | .SH Fortran Syntax |
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| 15 | .nf |
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| 16 | INCLUDE 'mpif.h' |
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| 17 | MPI_COMM_DUP(\fICOMM, NEWCOMM, IERROR\fP) |
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| 18 | INTEGER \fICOMM, NEWCOMM, IERROR\fP |
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| 19 | |
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| 20 | .SH C++ Syntax |
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| 21 | .nf |
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| 22 | #include <mpi.h> |
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| 23 | Intracomm Intracomm::Dup() const |
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| 24 | |
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| 25 | Intercomm Intercomm::Dup() const |
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| 26 | |
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| 27 | .SH INPUT PARAMETER |
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| 28 | .ft R |
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| 29 | .TP 1i |
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| 30 | comm |
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| 31 | Communicator (handle). |
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| 32 | |
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| 33 | .SH OUTPUT PARAMETERS |
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| 34 | .ft R |
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| 35 | .TP 1i |
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| 36 | newcomm |
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| 37 | Copy of comm (handle). |
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| 38 | .ft R |
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| 39 | .TP 1i |
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| 40 | IERROR |
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| 41 | Fortran only: Error status (integer). |
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| 42 | |
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| 43 | .SH DESCRIPTION |
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| 44 | .ft R |
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| 45 | MPI_Comm_dup duplicates the existing communicator comm with associated key |
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| 46 | 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"). |
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| 47 | |
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| 48 | .SH NOTES |
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| 49 | This operation is used to provide a parallel |
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| 50 | 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_dup 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. |
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| 51 | .sp |
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| 52 | This call applies to both intra- and intercommunicators. |
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| 53 | |
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| 54 | .SH ERRORS |
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| 55 | 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. |
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| 56 | .sp |
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| 57 | Before the error value is returned, the current MPI error handler is |
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| 58 | 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. |
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| 59 | |
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| 60 | |
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