MPI_WIN_CALL_ERRHANDLER(3)

💅 MPI_Win_call_errhandler(3) — Open MPI, section 3 🎀

okay so bestie, welcome to the MPI_Win_call_errhandler page ✨ — yeah it's an Open MPI man page, section 3, and it's literally all about passing the supplied error code to the error handler assigned to a window. sit down, hydrate, let's go 🫶

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✨ SYNTAX ✨

🌸 C Syntax

#include <mpi.h>

int MPI_Win_call_errhandler(MPI_Win win, int errorcode)

🦋 Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_WIN_CALL_ERRHANDLER(WIN, ERRORCODE, IERROR)
     INTEGER WIN, ERRORCODE, IERROR

🧚 Fortran 2008 Syntax

USE mpi_f08
MPI_Win_call_errhandler(win, errorcode, ierror)
     TYPE(MPI_Win), INTENT(IN) :: win
     INTEGER, INTENT(IN) :: errorcode
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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💖 INPUT PARAMETERS 💖

• win — the window that's holding the error handler, as a handle. your main character window tbh 👑
• errorcode — the MPI error code, an integer. this is the tea you're handing over 🍓

🌈 OUTPUT PARAMETER 🌈

• ierror — Fortran only, bestie: the error status, an integer. C girlies get a return value, Fortran girlies get this.

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💅 DESCRIPTION 💅

So what this actually does: it invokes the error handler that's assigned to the window win, and it hands that handler the supplied error code errorcode. simple. iconic. no cap.

And here's the good part ✨ — if the error handler was successfully called, AND the process is not aborted, AND the error handler returns, then this function returns MPI_SUCCESS. like, everybody came back alive, we love a happy ending 🫶

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⚠️ NOTES ⚠️

bestie listen to me. the default error handler is MPI_ERRORS_ARE_FATAL. so if you call this function and nobody changed the error handler for this window, it will abort the window processes. like, all of them. 😭 not a drill.

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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. that's just how it is, iykyk.

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 — the holy trinity fr fr:

• MPI_ERRORS_ARE_FATAL — causes the program to abort all connected MPI processes. dramatic but effective 💀
• 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. she's flexible 💅
• MPI_ERRORS_RETURN — returns an error code to the application. lowkey the chill one ✨

MPI applications can also implement their own error handlers by calling — build your own, main character energy 🎀:

• 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 assume you're safe 🙈

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_Win_create_errhandler
• MPI_Win_set_errhandler

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🌸 COPYRIGHT 🌸

2003-2026, The Open MPI Community 💜

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and that's the whole page bestie, no notes, periodt 💅✨ — shoutout to Open MPI and the Sep 11, 2026 date at the bottom, MPI_WIN_CALL_ERRHANDLER(3) out. 🎀🫶