MPI_COMM_CALL_ERRHANDLER(3)

💖 MPI_COMM_CALL_ERRHANDLER 💖

okay bestie, this is the MPI_Comm_call_errhandler page from the Open MPI manual, section 3, and it's literally about handing an error code straight to whatever error handler your communicator is holding. she's a messenger. an icon. let's go ✨

🦋 NAME 🦋

MPI_Comm_call_errhandler — passes the supplied error code to the error handler assigned to a communicator 💅

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✨ SYNTAX ✨

C Syntax

#include <mpi.h>

int MPI_Comm_call_errhandler(MPI_Comm comm, int errorcode)

Fortran Syntax

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

MPI_COMM_CALL_ERRHANDLER(COMM, ERRORCODE, IERROR)
    INTEGER COMM, ERRORCODE, IERROR

Fortran 2008 Syntax

USE mpi_f08

MPI_Comm_call_errhandler(comm, errorcode, ierror)
    TYPE(MPI_Comm), INTENT(IN) :: comm
    INTEGER, INTENT(IN) :: errorcode
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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🌸 INPUT PARAMETER 🌸

• comm — communicator with error handler (handle). she's the one holding the handler, so she's the one getting poked.
• errorcode — error code (integer). this is what you're serving up.

🎀 OUTPUT PARAMETERS 🎀

• ierror — Fortran only: Error status (integer). C besties get it as the return value instead, no cap.

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💫 DESCRIPTION 💫

So this function invokes the error handler assigned to the communicator comm, and it passes along the error code errorcode that you supplied. If the error handler was successfully called, and the process is not aborted, and the error handler returns — then this function returns MPI_SUCCESS. that's the whole flow, gorgeous 🫶

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👑 NOTES 👑

not me popping in to warn you but — bestie, read this one 💀

Users should note that the default error handler is MPI_ERRORS_ARE_FATAL. So calling this function will abort the processes in comm if the default error handler has not been changed. fr fr. she will end everything.

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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, and they are lowkey iconic:

• 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, 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.
• 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… don't count on surviving it, babe 😭

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

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💜 Copyright 💜

2003-2026, The Open MPI Community

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okay that's the whole page bestie — it's from the Open MPI manual, MPI_COMM_CALL_ERRHANDLER(3), and the little footer stamp at the bottom said Sep 10, 2026. so that's the source, the version vibe, and the date, all wrapped up with a bow 🎀 go forth and call your error handlers, just maybe set one first 💅✨ bye!! 🦋