MPI_COMM_GET_ERRHANDLER(3)

💖 MPI_COMM_GET_ERRHANDLER 💖

okay bestie, welcome to the Open MPI manual, page MPI_COMM_GET_ERRHANDLER(3). this one's short and sweet and honestly lowkey iconic. let's get into it. 🎀

✨ NAME ✨

MPI_Comm_get_errhandler — retrieves the error handler associated with a communicator. yes girl, we're doing a lil lookup. no cap.

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🌸 SYNTAX 🌸

C Syntax

#include <mpi.h>

int MPI_Comm_get_errhandler(MPI_Comm comm,
     MPI_Errhandler *errhandler)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_COMM_GET_ERRHANDLER(COMM, ERRHANDLER, IERROR)
     INTEGER COMM, ERRHANDLER, IERROR

Fortran 2008 Syntax

USE mpi_f08
MPI_Comm_get_errhandler(comm, errhandler, ierror)
     TYPE(MPI_Comm), INTENT(IN) :: comm
     TYPE(MPI_Errhandler), INTENT(OUT) :: errhandler
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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🫶 INPUT PARAMETER 🫶

• comm — the communicator, as a handle. it's the thing you're snooping on. 👀

💅 OUTPUT PARAMETERS 💅

• errhandler — the new error handler for the communicator (handle). this is where the answer lands, bestie.
• ierror — Fortran only: error status (integer). classic Fortran behavior, slaying in the last argument as always.

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🦋 DESCRIPTION 🦋

so MPI_Comm_get_errhandler retrieves the error handler that's currently associated with a communicator. that's it, that's the whole vibe. it's literally identical to MPI_Errhandler_get, except that one is deprecated — so like, don't use it, use this one instead, periodt. 💀

it returns in errhandler (a handle to) the error handler that is currently associated with communicator comm.

Example: picture a library function at its entry point — it can register the current error handler for a communicator, set its own private error handler for that communicator, and then restore the previous error handler before exiting. so cute, so tidy. ✨

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😭 ERRORS 😭

almost all MPI routines return an error value — C routines hand it back as the return result of the function, and Fortran routines drop it in the last argument. that's just how they do it.

before the error value is returned, the current MPI error handler associated with the communication object (like a communicator, window, or file) gets called. if no communication object is associated with the MPI call, then the call counts as 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. and 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 ships three predefined error handlers you can use, and they're giving very different energies:

• MPI_ERRORS_ARE_FATAL — causes the program to abort all connected MPI processes. nuclear. 💀
• 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, it 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, it aborts only the local process. main character energy, but locally.
• MPI_ERRORS_RETURN — returns an error code to the application. the chill one. 🧚

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. like, it might just not. be aware. 🙈

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. 📚

See also:

• MPI_Comm_create_errhandler
• MPI_Comm_set_errhandler

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👑 Copyright 👑

<copyright>2003-2026, The Open MPI Community</copyright>

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and that's the whole page, bestie!! 🎀✨ this was the Open MPI MPI_COMM_GET_ERRHANDLER(3) man page, dated Sep 10, 2026 — screenshot it, cite it, cite your sources fr fr. go forth and retrieve those error handlers. you ate. 💅🦋💜