MPI_FILE_CLOSE(3)

💖 MPI_File_close 💖

okay bestie, so this is a page from the Open MPI manual, and it's literally all about saying byeee to a file. yes, THE MPI_File_close — closes a file (collective). collective, meaning everybody's in on it, no sneaky solo exits. 🫶

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✨ NAME ✨

MPI_File_close — Closes a file (collective). that's the whole vibe. 📁✌️

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✨ SYNTAX ✨

C Syntax 🌸

#include <mpi.h>

int MPI_File_close(MPI_File *fh)

Fortran Syntax 🌸

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

Fortran 2008 Syntax 🌸

USE mpi_f08
MPI_File_close(fh, ierror)
     TYPE(MPI_File), INTENT(INOUT) :: fh
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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✨ INPUT/OUTPUT PARAMETER ✨

• fh — the file handle, and it's a handle. it goes in AND out, it's giving bidirectional main character energy. 💅

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✨ OUTPUT PARAMETER ✨

• ierror — Fortran only, bestie, C doesn't get one of these. it's the error status, and it's an integer. 🍓

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✨ DESCRIPTION ✨

okay so here's the tea ☕: MPI_File_close first synchronizes file state, and then closes the file associated with fh. in that order. sync first, close second, no skipping steps.

and like, MPI_File_close is a collective routine. periodt. 🎀

⚠️ real talk though: the user is responsible for making sure that all outstanding requests associated with fh have completed before calling MPI_File_close. that's on you, not on MPI. don't be out here closing files with requests still hanging, iykyk. 😭

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✨ ERRORS ✨

ngl, almost every MPI routine returns an error value, and the way it comes back depends on your language:

• C routines → return it as the return result of the function
• Fortran routines → put it in the last argument

before that error value even gets returned, the current MPI error handler associated with the communication object (think communicator, window, file) gets called. 🦋

if there's no communication object associated with the MPI call, then the call is considered attached to MPI_COMM_SELF, and it'll call the associated MPI error handler. and when MPI_COMM_SELF isn't initialized (like before MPI_Init/MPI_Init_thread, after MPI_Finalize, or when you're using the Sessions Model exclusively) the error raises the initial error handler. ✨

that 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
• the info key to MPI_Comm_spawn/MPI_Comm_spawn_multiple

and if no other appropriate error handler has been set? then MPI_ERRORS_RETURN gets called for MPI I/O functions, and MPI_ERRORS_ABORT gets called for all other MPI functions. that's just how it is. 💀

Open MPI ships three predefined error handlers you can use, and they are:

• MPI_ERRORS_ARE_FATAL — Causes the program to abort all connected MPI processes. dramatic much? yes. on purpose. 🔥
• 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. 💜

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

🚨 bestie heads up: note that MPI does not guarantee that an MPI program can continue past an error. like, it might just be over. no cap.

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. protecting the brand since 2003, we love to see it. 💖

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and that's the whole page, bestie!! this one came straight out of the Open MPI docs, dated Sep 10, 2026, and it lives at page MPI_FILE_CLOSE(3). go forth and close your files responsibly, mwah 💅✨🎀