MPIX_COMM_IS_REVOKED(3)

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💅 MPIX_COMM_IS_REVOKED(3) — the mpix_comm_is_revoked page, bestie edition ✨

Okay so sit down, grab a boba, because we're talking about a manual page — yes the mpix_comm_is_revoked(3) one — and honestly? it ate. 🫶

This page lives inside Open MPI, and it's part of the User Level Fault Mitigation ULFM extension <#ulfm-label>. If you're here you're probably doing the hardcore fault-tolerance stuff and I am so proud of you 💖

✨ SYNTAX ✨

🩷 C Syntax

#include <mpi.h>
#include <mpi-ext.h>

int MPIX_Comm_is_revoked(MPI_Comm comm, int *flag)

🩵 Fortran Syntax

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

MPIX_COMM_IS_REVOKED(COMM, FLAG, IERROR)
     INTEGER COMM, IERROR
     LOGICAL FLAG

💜 Fortran 2008 Syntax

USE mpi_f08
USE mpi_ext_f08

MPIX_Comm_is_revoked(comm, flag, ierror)
     TYPE(MPI_Comm), INTENT(IN) :: comm
     LOGICAL, INTENT(OUT) :: flag
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

📥 INPUT PARAMETERS

  • comm — the communicator, aka the handle. that's it, that's the whole input list. lowkey iconic for her to need so little 🌸

📤 OUTPUT PARAMETERS

  • flag — true if the communicator is revoked. literally the whole point of this function 💅
  • ierror — Fortran only, bestie: the error status (an integer).

🌈 DESCRIPTION

So it returns flag = true if the communicator attached to the handle comm is revoked at the calling process. Otherwise it returns flag = false. And the vibe? the operation is local. no network round trips, no waiting on anybody, just a lil local check. periodt. ⭐

😭 HOW CAN A COMMUNICATOR BECOME REVOKED

A communicator can get its revocation arc when:

  1. the user calls the MPIX_Comm_revoke <#mpix-comm-revoke> procedure on comm to revoke the communicator at the local process;
  2. an MPI operation raised the error class MPIX_ERR_REVOKED because another process called the MPIX_Comm_revoke <#mpix-comm-revoke> procedure on comm;
  3. the communicator has the info key mpi_error_range set to group or universe, in which case the failure of any process in, respectively, the group of comm or the MPI universe caused an operation to raise an error of class MPIX_ERR_REVOKED.

🧚 REVOKE PROPAGATION AND ORDERING

heads up bestie, multithreading jumpscare 🙈

In a multithreaded application, a thread calling MPIX_Comm_is_revoked may return flag = true before the operation that raises the first exception of class MPIX_ERR_REVOKED has actually completed in a concurrent thread. so like. the vibes travel faster than the paperwork. noted. 💀

🔥 EFFECT OF A COMMUNICATOR REVOCATION

Once a communicator has been revoked at an MPI process, all subsequent non-local operations on that communicator (minus the lil exceptions listed down below ⬇️) are considered local and must complete by raising an error of class MPIX_ERR_REVOKED at that MPI process. no cap. it's giving "sorry babe, this comm is closed". 🚫

👑 OPERATIONS ON A REVOKED COMMUNICATOR

These following operations never raise an error of class MPIX_ERR_REVOKED, and they complete with their normal semantics even on a revoked communicator. the survivors. the main characters. 🎀

  • MPIX_Comm_agree <#mpix-comm-agree>
  • MPIX_Comm_iagree <#mpix-comm-iagree>
  • MPIX_Comm_shrink <#mpix-comm-shrink>
  • MPIX_Comm_ishrink <#mpix-comm-ishrink>

💀 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. classic split, 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>/MPI_Init_thread <#mpi-init-thread>, after MPI_Finalize <#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 <#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>/MPI_Comm_spawn_multiple <#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.
  • 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 <#mpi-abort> was called on that communicator. If called on a window or file, acts as if MPI_Abort <#mpi-abort> was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, 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 <#mpi-comm-create-errhandler> then MPI_Comm_set_errhandler <#mpi-comm-set-errhandler>
  • MPI_File_create_errhandler <#mpi-file-create-errhandler> then MPI_File_set_errhandler <#mpi-file-set-errhandler>
  • MPI_Session_create_errhandler <#mpi-session-create-errhandler> then MPI_Session_set_errhandler <#mpi-session-set-errhandler> or at MPI_Session_init <#mpi-session-init>
  • MPI_Win_create_errhandler <#mpi-win-create-errhandler> then MPI_Win_set_errhandler <#mpi-win-set-errhandler>
⚠️ Note that MPI does not guarantee that an MPI program can continue past an error. fr fr. no promises. 🫠

See the MPI man page <#open-mpi> for a full list of MPI error codes <#open-mpi-errors>.

See the Error Handling section of the MPI-3.1 standard for more information.

See also:

  • MPIX_Comm_revoke <#mpix-comm-revoke>
  • MPIX_Comm_agree <#mpix-comm-agree>
  • MPIX_Comm_shrink <#mpix-comm-shrink>

2003-2026, The Open MPI Community

and that's the whole page bestie!! ✨🦋💖 This was MPIX_COMM_IS_REVOKED(3) from Open MPI, dated Sep 10, 2026, copyrighted 2003-2026, The Open MPI Community. go forth and revoke responsibly, mwah 💅🍓

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