MPI_FILE_SYNC(3)

💖 MPI_File_sync 💖 — bestie, your file is literally synced now ✨

okay so this is the Open MPI manual page for MPI_FILE_SYNC(3). Yes it's a man page. Yes it's about MPI I/O. Yes we're gonna make it cute. Let's go 🦋

Headings say:

🌸 NAME 🌸

MPI_File_sync — makes semantics consistent for data-access operations (collective). no cap, that's the whole vibe 💅

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✨ SYNTAX ✨

C Syntax

#include <mpi.h>

int MPI_File_sync(MPI_File fh)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_FILE_SYNC(FH, IERROR)
     INTEGER FH, IERROR

Fortran 2008 Syntax

USE mpi_f08
MPI_File_sync(fh, ierror)
     TYPE(MPI_File), INTENT(IN) :: fh
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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📥 INPUT PARAMETER 📥

• fh — the File handle (a handle, bestie 🫶).

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📤 OUTPUT PARAMETER 📤

• ierror — Fortran only, it's the Error status (integer). Fortran girlies get their error handed to them in the last argument, iconic honestly 💜

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💫 DESCRIPTION 💫

Calling MPI_File_sync with fh causes all previous writes to fh by the calling process to be written to permanent storage. like, actually on disk, fr fr 🍓

And if other processes have made updates to permanent storage, then all such updates become visible to subsequent reads of fh by the calling process. so you see their glow-up too ✨

⚠️ MPI_File_sync is a collective operation. and like, the user is responsible for ensuring that all nonblocking requests on fh have been completed before calling MPI_File_sync. Otherwise, the call to MPI_File_sync is erroneous. not me forgetting to wait on my nonblocking requests 😭 please don't do that bestie.

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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. classic division of labor 💅

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. so that's the whole chain of who-gets-called, iykyk 🧚

Open MPI includes three predefined error handlers that can be used:

• MPI_ERRORS_ARE_FATAL — Causes the program to abort all connected MPI processes. it's giving no survivors 💀
• 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 chill one, respectfully 🫶

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. that's a big deal, bestie — past the error there might just be nothing 🌈

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. go read it, it's the lore 📚

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👑 Copyright 👑

2003-2026, The Open MPI Community

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okay that's the whole page, you ate that 🎀 this was Open MPI, page MPI_FILE_SYNC(3), dated Sep 10, 2026 — mwah, go sync something 💖✨🦋