---
name: "MPIX_Comm_is_revoked"
section: "3"
platform: "linux"
package: "openmpi"
version: "5.0.11-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/MPIX_Comm_is_revoked"
---

# MPIX\_Comm\_is\_revoked(3)

*MPIX\_Comm\_is\_revoked* - Test if a communicator is revoked.

This is part of the User Level Fault Mitigation *ULFM extension*.

## 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**: Communicator (handle).

## OUTPUT PARAMETERS

- •

  **flag**: *true* if the communicator is revoked.

- •

  **ierror**: Fortran only: Error status (integer).

## DESCRIPTION

Returns *flag = true* if the communicator associated with the handle *comm* is revoked at the calling process. It returns *flag = false* otherwise. The operation is local.

## HOW CAN A COMMUNICATOR BECOME REVOKED

A communicator can become revoked when

- 1\.

  the user calls the *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* 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

Note that 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 completed in a concurrent thread.

## EFFECT OF A COMMUNICATOR REVOCATION

Once a communicator has been revoked at an MPI process, all subsequent non-local operations on that communicator (with some exceptions listed below), are considered local and must complete by raising an error of class MPIX\_ERR\_REVOKED at that MPI process.

## OPERATIONS ON A REVOKED COMMUNICATOR

The following operations never raise an error of class MPIX\_ERR\_REVOKED, and complete with their normal semantics on a revoked communicator.

- •

  *MPIX\_Comm\_agree*

- •

  *MPIX\_Comm\_iagree*

- •

  *MPIX\_Comm\_shrink*

- •

  *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.

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.

- •

  **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, 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, 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.

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:**

- •

  *MPIX\_Comm\_revoke*

- •

  *MPIX\_Comm\_agree*

- •

  *MPIX\_Comm\_shrink*

## COPYRIGHT

2003-2026, The Open MPI Community