MPI_WIN_FLUSH_LOCAL(3)

💫 MPI_WIN_FLUSH_LOCAL 💫

bestie, welcome to the Open MPI manual page for MPI_Win_flush_local and MPI_Win_flush_local_all — the twin routines that go "okay we're done here" on the origin side. sit down, hydrate, let's go 🫶

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✨ NAME ✨

MPI_Win_flush_local, MPI_Win_flush_local_all — Complete all outstanding RMA operations at both the origin

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✨ SYNTAX ✨

🎀 C Syntax

#include <mpi.h>

int MPI_Win_flush_local (int rank, MPI_Win win)

int MPI_Win_flush_local_all (MPI_Win win)

🎀 Fortran Syntax

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

MPI_WIN_FLUSH_LOCAL_ALL(WIN, IERROR)
     INTEGER WIN, IERROR

🎀 Fortran 2008 Syntax

USE mpi_f08
MPI_Win_flush_local(rank, win, ierror)
     INTEGER, INTENT(IN) :: rank
     TYPE(MPI_Win), INTENT(IN) :: win
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

MPI_Win_flush_local_all(win, ierror)
     TYPE(MPI_Win), INTENT(IN) :: win
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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✨ INPUT PARAMETERS ✨

• rank — Rank of window (nonnegative integer). the specific bestie you're flushing at 💅
• win — Window object (handle). your whole window situation ✨

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✨ OUTPUT PARAMETER ✨

• ierror — Fortran only: Error status (integer).

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✨ DESCRIPTION ✨

okay so here's the tea 🍓

MPI_Win_flush_local locally completes at the origin all outstanding RMA operations initiated by the calling process to the target process specified by rank on the specified window. for example, after this routine completes, the user may reuse any buffers provided to put, get, or accumulate operations.

MPI_Win_flush_local_all locally completes at the origin all outstanding RMA operations to all targets. it's the "everybody get flushed" version 👑

⚠️ real talk: these can only be called from within a passive target epoch. don't try it anywhere else, it's giving invalid and you will not be slaying.

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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. 💀
• 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:

• MPI_Win_flush
• MPI_Win_lock
• MPI_Win_lock_all

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✨ Copyright ✨

2003-2026, The Open MPI Community

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okay that's the whole page bestie, you ate it up 💅✨ this lil masterpiece is straight from the Open MPI docs, dated Sep 10, 2026, and it's still rocking the MPI_WIN_FLUSH_LOCAL(3) title in the header up top. go flush something local, you main character 🦋💖