MPI_COMM_DUP_WITH_INFO(3)

💖 MPI_COMM_DUP_WITH_INFO(3) — the Open MPI glow-up 💖

okay bestie, so this is a page from Open MPI, and it's all about MPI_Comm_dup_with_info — the communicator duplication queen who lets you swap out the info hints herself. no cap. 🎀

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✨ NAME ✨

MPI_Comm_dup_with_info — Duplicates an existing communicator using provided info.

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🌸 SYNTAX 🌸

C Syntax

#include <mpi.h>

int MPI_Comm_dup_with_info(MPI_Comm comm, MPI_Info info, MPI_Comm *newcomm)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'

MPI_COMM_DUP_WITH_INFO(COMM, INFO, NEWCOMM, IERROR)
    INTEGER COMM, INFO, NEWCOMM, IERROR

Fortran 2008 Syntax

USE mpi_f08

MPI_Comm_dup_with_info(comm, info, newcomm, ierror)
    TYPE(MPI_Comm), INTENT(IN) :: comm
    TYPE(MPI_Info), INTENT(IN) :: info
    TYPE(MPI_Comm), INTENT(OUT) :: newcomm
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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🫶 INPUT PARAMETER 🫶

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

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💅 OUTPUT PARAMETERS 💅

• newcomm : Copy of comm (handle).
• ierror : Fortran only: Error status (integer).

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🦋 DESCRIPTION 🦋

MPI_Comm_dup_with_info acts exactly like MPI_Comm_dup — literally exactly — except that the info hints that were hanging out with the communicator comm are not duplicated into newcomm. the way that works is: the hints you pass in through the argument info get associated with the output communicator newcomm instead. it's giving "new communicator, new hints, who dis." 💅

if you wanna know which info keys are even recognized, go see MPI_Comm_set_info for the whole list. 👑

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🔥 NOTES 🔥

this operation is used to give a parallel library call a duplicate communication space that has the same properties as the original communicator. and yes, that includes any attributes (see below) and topologies (see the “Process Topologies” chapter in the MPI Standard <https://www.mpi-forum.org/docs/>).

this call is valid even if there are pending point-to-point communications involving the communicator comm. so you can duplicate mid-conversation, no drama. 💖

a classic move is: call MPI_Comm_dup_with_info at the beginning of the parallel call, and then MPI_Comm_free that duplicated communicator at the end of the call. but honestly, other models of communicator management are also possible — you do you, main character. ✨

this call applies to both intra- and intercommunicators. love that for her. 🌈

⚠️ okay heads up, this part is important: it is not defined by the MPI standard what happens if the attribute copy callback invokes other MPI functions. and in Open MPI specifically, 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. so like... don't. seriously. 😭

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💀 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/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.

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 by calling:

• MPI_Comm_create_errhandler then MPI_Comm_set_errhandler
• MPI_File_create_errhandler then MPI_File_set_errhandler
• MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init
• MPI_Win_create_errhandler then MPI_Win_set_errhandler

💀 note that MPI does not guarantee that an MPI program can continue past an error. so like... it's giving permanent. 🙈

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

see the Error Handling section of the MPI-3.1 standard for more information.

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👑 SEE ALSO 👑

• MPI_Comm_dup

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🎀 Copyright 🎀

2003-2026, The Open MPI Community

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and that's the whole page, bestie!! 🫶 this was MPI_COMM_DUP_WITH_INFO(3) from the Open MPI fam, last touched Sep 10, 2026 — go duplicate something iconic and remember: new communicator, new hints, same flawless energy. slay. 💖✨🌸