MPI_FILE_GET_BYTE_OFFSET(3)

💅 MPI_FILE_GET_BYTE_OFFSET(3) ✨

okay so bestie, welcome to the Open MPI manual page for MPI_FILE_GET_BYTE_OFFSET — third section of the manual, and honestly? it's giving "small function, big main character energy." let's get into it 🫶

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🌸 NAME 🌸

MPI_File_get_byte_offset — converts a view-relative offset into an absolute byte position. literally that's her whole job and she does it slayfully ✨

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🎀 SYNTAX 🎀

💖 C Syntax

#include <mpi.h>

int MPI_File_get_byte_offset(MPI_File fh, MPI_Offset offset,
     MPI_Offset *disp)

🦋 Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_FILE_GET_BYTE_OFFSET(FH, OFFSET, DISP, IERROR)
     INTEGER FH, IERROR
     INTEGER(KIND=MPI_OFFSET_KIND)   OFFSET, DISP

🧚 Fortran 2008 Syntax

USE mpi_f08
MPI_File_get_byte_offset(fh, offset, disp, ierror)
     TYPE(MPI_File), INTENT(IN) :: fh
     INTEGER(KIND=MPI_OFFSET_KIND), INTENT(IN) :: offset
     INTEGER(KIND=MPI_OFFSET_KIND), INTENT(OUT) :: disp
     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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💜 INPUT PARAMETERS 💜

• fh — your file handle, aka the handle. the whole vibe check of "which file are we even talking about" 🗂️
• offset — the offset, an integer. this is the view-relative girly who's about to get converted ✨

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🍓 OUTPUT PARAMETERS 🍓

• disp — the absolute byte position of offset, an integer. she's the final form 💅
• ierror — Fortran only, bestie: error status, integer. 🙈

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🔥 DESCRIPTION 🔥

so MPI_File_get_byte_offset takes an offset that was specified for the current view and converts it into its corresponding displacement value — aka the absolute byte position from the beginning of the file. the absolute byte position of offset relative to the current view of fh comes back to you in disp. no cap, that's it, that's the tea ☕✨

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💀 ERRORS 💀

like, 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. 😭

before that error value comes back, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. and 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 the info key to MPI_Comm_spawn/MPI_Comm_spawn_multiple. and 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. okay that was a lot, but you got this 🫶

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? yes. effective? also yes 💀
• 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. respectful, hands your problem back to you 🎁

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. iykyk 📚✨

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👑 COPYRIGHT 👑

2003-2026, The Open MPI Community

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and that's the whole page, bestie! 🌈 mwah 💋 — with love from the Open MPI squad, dated Sep 11, 2026, signing off as MPI_FILE_GET_BYTE_OFFSET(3) 🎀🦋💖