MPI_FILE_GET_ATOMICITY(3)

💅 MPI_File_get_atomicity 💅

okay bestie, buckle up — this is the MPI_File_get_atomicity page from the Open MPI manual, and it's literally just gonna tell you whether your file is in atomic mode or not. that's it. that's the whole vibe. let's get into it 🫶

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✨ NAME ✨

MPI_File_get_atomicity — returns the current consistency semantics for data-access operations. no cap, that's the entire job. 🎀

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🌈 SYNTAX 🌈

🦋 C Syntax 🦋

#include <mpi.h>

int MPI_File_get_atomicity(MPI_File fh, int *flag)

🦋 Fortran Syntax 🦋

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

🦋 Fortran 2008 Syntax 🦋

USE mpi_f08
MPI_File_get_atomicity(fh, flag, ierror)
     TYPE(MPI_File), INTENT(IN) :: fh
     LOGICAL, INTENT(OUT) :: flag
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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🍓 INPUT PARAMETER 🍓

• fh — the file handle, bestie. it's a handle. that's the whole thing. 💖

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🌸 OUTPUT PARAMETER 🌸

• flag — true if atomic mode is enabled, false if nonatomic mode is enabled (it's a boolean, so like... yes or no, no in-between 💀).
• ierror — Fortran only, gorj: this is your error status (integer).

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👑 DESCRIPTION 👑

so MPI_File_get_atomicity returns the current consistency semantics for data access operations on the set of file handles created by one collective MPI_File_open. if flag is true, atomic mode is currently enabled. if flag is false, nonatomic mode is currently enabled. it's giving "just tell me which one it is" and honestly? iconic. ✨

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💀 ERRORS 💀

almost all MPI routines return an error value — and here's the tea: C routines return it as the return result of the function itself, and Fortran routines return it in the last argument. periodt.

before that error value ever comes back to you, the current MPI error handler associated with the communication object (e.g., communicator, window, file) gets called. and if there's, like, no communication object 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. and you can change that initial error handler — by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using the World model, or via the mpi_initial_errhandler CLI argument to mpiexec, or the 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. slay. 💅

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

• MPI_ERRORS_ARE_FATAL — causes the program to abort all connected MPI processes. 😭 yeah. all of them.
• 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, it 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, it 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

⚠️ note that MPI does not guarantee that an MPI program can continue past an error. so like... don't count on it, bestie. 🙈

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

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and that's the whole page, bestie!! 💖 this gorgeous little number is from the Open MPI manual, dated Sep 11, 2026 — go forth and check your atomicity, you absolute main character. you ate. 👑✨