MPI_COMM_GET_ERRHANDLER(3)

💖 NAME 💖

This is the MPI_COMM_GET_ERRHANDLER(3) page from Open MPI, bestie. It’s giving “grab the error handler that’s currently attached to a communicator.”

MPI_Comm_get_errhandler — retrieves the error handler associated with a communicator. 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. That’s the main character here.

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💜 OUTPUT PARAMETERS 💜

• errhandler — the new error handler for the communicator, as a handle.
• ierror — Fortran only: the error status, as an integer.

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🌈 DESCRIPTION 🌈

MPI_Comm_get_errhandler retrieves the error handler that is currently associated with a communicator. This call is literally identical to MPI_Errhandler_get, but bestie… the use of MPI_Errhandler_get is deprecated. So maybe don’t make that your whole personality.

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

Example time: a library function may register at its entry point the current error handler for a communicator, set its own private error handler for this communicator, and restore the previous error handler before exiting. That’s the whole flex. 💅

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🔥 ERRORS 🔥

Heads up, bestie: almost all MPI routines return an error value. C routines give it as the return result of the function, and Fortran routines put it 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. Very dramatic. Very final. 💀
• 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 assume it’s gonna bounce back, okay? 🫶

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_create_errhandler
• MPI_Comm_set_errhandler

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👑 COPYRIGHT 👑

2003-2026, The Open MPI Community

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💖 That’s the page, bestie — from Open MPI, dated Sep 11, 2026. MPI_COMM_GET_ERRHANDLER(3), signing off! 💖