MPI_RGET(3)

📦

version 5.0.10 · 4 versions

🦋 MPI_RGET — the Open MPI manual page, bestie edition 🦋

okay so. this is the page for MPI_Get and MPI_Rget, and they live in Open MPI's section 3 (library calls, iykyk). TL;DR: they copy data from the target memory to the origin. that's the whole vibe. and MPI_Rget is the async one that hands you a request handle so you can vibe-check it later. no cap. 💅

✨ SYNTAX ✨

🍓 C Syntax

#include <mpi.h>

MPI_Get(void *origin_addr, int origin_count, MPI_Datatype
    origin_datatype, int target_rank, MPI_Aint target_disp,
    int target_count, MPI_Datatype target_datatype, MPI_Win win)

MPI_Rget(void *origin_addr, int origin_count, MPI_Datatype
     origin_datatype, int target_rank, MPI_Aint target_disp,
     int target_count, MPI_Datatype target_datatype, MPI_Win win,
         MPI_Request *request)

🌸 Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'

MPI_GET(ORIGIN_ADDR, ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK,
    TARGET_DISP, TARGET_COUNT, TARGET_DATATYPE, WIN, IERROR)
    <type> ORIGIN_ADDR(*)
    INTEGER(KIND=MPI_ADDRESS_KIND) TARGET_DISP
    INTEGER ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK,
    TARGET_COUNT, TARGET_DATATYPE, WIN, IERROR

MPI_RGET(ORIGIN_ADDR, ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK,
     TARGET_DISP, TARGET_COUNT, TARGET_DATATYPE, WIN, REQUEST, IERROR)
     <type> ORIGIN_ADDR(*)
     INTEGER(KIND=MPI_ADDRESS_KIND) TARGET_DISP
     INTEGER ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK,
     TARGET_COUNT, TARGET_DATATYPE, WIN, REQUEST, IERROR

🧚 Fortran 2008 Syntax

USE mpi_f08

MPI_Get(origin_addr, origin_count, origin_datatype, target_rank,
        target_disp, target_count, target_datatype, win, ierror)
    TYPE(*), DIMENSION(..), ASYNCHRONOUS :: origin_addr
    INTEGER, INTENT(IN) :: origin_count, target_rank, target_count
    TYPE(MPI_Datatype), INTENT(IN) :: origin_datatype, target_datatype
    INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: target_disp
    TYPE(MPI_Win), INTENT(IN) :: win
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror

MPI_Rget(origin_addr, origin_count, origin_datatype, target_rank,
    target_disp, target_count, target_datatype, win, request,
        ierror)
    TYPE(*), DIMENSION(..), ASYNCHRONOUS :: origin_addr
    INTEGER, INTENT(IN) :: origin_count, target_rank, target_count
    TYPE(MPI_Datatype), INTENT(IN) :: origin_datatype, target_datatype
    INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: target_disp
    TYPE(MPI_Win), INTENT(IN) :: win
    TYPE(MPI_Request), INTENT(OUT) :: request
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror

📥 INPUT PARAMETERS 📥

origin_addr — the initial address of the origin buffer (a choice, bestie, it's a choice).
origin_count — number of entries in the origin buffer. nonnegative integer, so pls no negatives. 😭
origin_datatype — data type of each entry in the origin buffer (handle).
target_rank — rank of the target. nonnegative integer.
target_disp — displacement from window start to the beginning of the target buffer. nonnegative integer.
target_count — number of entries in the target buffer. nonnegative integer.
target datatype — datatype of each entry in target buffer (handle).
win — the window object used for communication (handle).

📤 OUTPUT PARAMETER 📤

request — MPI_Rget: the RMA request. your little receipt. 🧾
ierror — Fortran only: error status (integer).

💖 DESCRIPTION 💖

MPI_Get copies data from the target memory to the origin, kinda like MPI_Put except the direction of the data transfer is fully reversed. it's giving "put, but backwards." 🔄

the origin_datatype may not specify overlapping entries in the origin buffer — do not do that, it's not the move. the target buffer must be contained within the target window, and the copied data must fit, without truncation, in the origin buffer. and here's the big one: only processes within the same node can access the target window. yep. same node only. that's just how it is. 🙈

MPI_Rget is similar to MPI_Get, except that it allocates a communication request object and associates it with the request handle (the argument request) that can be used to wait or test for completion. the completion of an MPI_Rget operation indicates that the data is available in the origin buffer. and if origin_addr points to memory attached to a window, then the data becomes available in the private copy of this window. so when it's done, it's actually done. ✨

💀 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. periodt. 🫶

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_Put

👑 Copyright 👑

2003-2026, The Open MPI Community

and that's the whole page, bestie 🎀 you just read the MPI_RGET(3) man page from Open MPI — copyright 2003-2026, The Open MPI Community, dated Sep 10, 2026. slay, go get that data. 💖✨🦋

📦 where this page comes from

ubuntu stonking: openmpi-doc 5.0.10-6 · other
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-11-03: a language model's rewrite of the original, under its terms