MPI_STATUS_SET_CANCELLED(3)

💖 MPI_STATUS_SET_CANCELLED(3) 💖

okay bestie, welcome to the Open MPI manual, section 3. this one's all about MPI_Status_set_cancelled, and no cap it's a tiny little function with a big job. pull up a chair, grab a boba, let's go 🧋✨

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✨ NAME ✨

MPI_Status_set_cancelled — sets status to indicate a request has been canceled. lowkey iconic behavior, fr fr 💅

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🌸 SYNTAX 🌸

C Syntax 💜

#include <mpi.h>

int MPI_Status_set_cancelled(MPI_Status *status, int flag)

Fortran Syntax 🦋

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_STATUS_SET_CANCELLED(STATUS, FLAG, IERROR)
     INTEGER STATUS(MPI_STATUS_SIZE), IERROR
     LOGICAL FLAG

Fortran 2008 Syntax 🎀

USE mpi_f08
MPI_Status_set_cancelled(status, flag, ierror)
     TYPE(MPI_Status), INTENT(INOUT) :: status
     LOGICAL, INTENT(OUT) :: flag
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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🌈 INPUT/OUTPUT PARAMETER 🌈

• status — the status you're attaching that cancel flag to (status). it's getting ✨modified✨ bestie, so it's in-out.

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🍓 INPUT PARAMETER 🍓

• flag — if true, it means the request was canceled (logical). basically you're telling the status "yeah girl, this one got canceled."

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🌟 OUTPUT PARAMETER 🌟

• ierror — Fortran only: error status (integer). the classic.

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💫 DESCRIPTION 💫

so here's the tea ☕: if flag is set to true, then a subsequent call to MPI_Test_cancelled(status, flag*) will also return flag = true. otherwise it'll return false. that's it. that's the whole vibe check. simple, clean, does exactly what it says on the tin 💖

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👑 NOTES 👑

okay listen, this is the part where I need you to pay attention, bestie, because it's giving "please don't do this" energy 🙈

Users are advised not to reuse the status fields for values other than those for which they were intended. Doing so may lead to unexpected results when using the status object. for example, calling MPI_Get_elements may cause an error if the value is out of range — or, plot twist, it may be impossible to detect such an error at all. 💀 terrifying, I know.

the extra_state argument that comes with a generalized request can be used to return information that doesn't logically belong in status. so like, use that instead, queen.

and furthermore — modifying the values in a status that was set internally by MPI, such as MPI_Recv, may lead to unpredictable results and is strongly discouraged. like, MPI set that up itself, don't go rearranging the furniture in someone else's house 🏠🚫

ngl this whole section is just MPI saying "hands off my internals" and honestly? fair.

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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.

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. 💀 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, 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. the polite one 🫶

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. bestie. handle your errors.

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 — shoutout to the whole Open MPI community, absolute legends, carrying this stack on their backs since 2003 👑

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and that's the page!! you ate that, bestie. this was MPI_STATUS_SET_CANCELLED(3) from Open MPI, last touched Sep 10, 2026. go set some cancel flags responsibly — and remember: don't touch the status fields you weren't meant to touch 💅✨🦋