MPI_WIN_CREATE_ERRHANDLER(3)

💖 MPI_WIN_CREATE_ERRHANDLER(3) 💖

okay bestie, welcome to the Open MPI manual, page MPI_WIN_CREATE_ERRHANDLER(3). sit down, grab a lil snack, we're building an error handler for a window and honestly? it's giving ✨customized✨.

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🌸 NAME 🌸

MPI_Win_create_errhandler — makes an error handler for a window 💅

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✨ SYNTAX ✨

🎀 C Syntax

#include <mpi.h>

int MPI_Win_create_errhandler(MPI_Win_errhandler_function *function,
     MPI_Errhandler *errhandler)

🎀 Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_WIN_CREATE_ERRHANDLER(FUNCTION, ERRHANDLER, IERROR)
     EXTERNAL FUNCTION
     INTEGER ERRHANDLER, IERROR

🎀 Fortran 2008 Syntax

USE mpi_f08
MPI_Win_create_errhandler(win_errhandler_fn, errhandler, ierror)
     PROCEDURE(MPI_Win_errhandler_function) :: win_errhandler_fn
     TYPE(MPI_Errhandler), INTENT(OUT) :: errhandler
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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💀 DEPRECATED TYPE NAME NOTE 💀

so MPI-2.2 deprecated the MPI_Win_errhandler_fn type in favor of MPI_Win_errhandler_function. and Open MPI? she supports both names, no cap (like, the _fn names are literally typedefs to the _function names). so if you're out here still using the old name, you're fine, we got you 🫶

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🌈 INPUT PARAMETER 🌈

• function — your user-defined error-handling procedure (a function, obviously 💁‍♀️)

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⭐ OUTPUT PARAMETERS ⭐

• errhandler — the MPI error handler (it's a handle bestie)
• ierror — Fortran only: the error status (an integer)

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👑 DESCRIPTION 👑

MPI_Win_create_errhandler should be, in C, a function of type MPI_Win_errhandler_function, which is defined as

typedef void MPI_Win_errhandler_function(MPI Win *, int *, ...);

first argument = the window in use, second argument = the error code to be returned. simple as that, periodt.

In Fortran, the user routine should be of the form:

SUBROUTINE WIN_ERRHANDLER_FUNCTION(WIN, ERROR_CODE, ...)
    INTEGER WIN, ERROR_CODE

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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. keep that in mind fr fr.

Before the error value is returned, the current MPI error handler associated with the communication object (like, a communicator, window, file, whatever) 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. that 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 the 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.

ngl that's a whole lot of fallback logic, and it's all load-bearing. don't skip it 💖

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, 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 ← that's us, hiii 🎀

Note that MPI does not guarantee that an MPI program can continue past an error. so like… don't bet on it.

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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📜 Copyright 📜

2003-2026, The Open MPI Community

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and that's the whole page bestie!! you just read a real life Open MPI man page and honestly? iconic behavior 💅✨ this was MPI_WIN_CREATE_ERRHANDLER(3) from the Open MPI crew, dated Sep 10, 2026 — copyright 2003-2026, The Open MPI Community. go forth and handle your errors, mwah 🦋💖