--- name: "MPI_Get.openmpi" section: "3" platform: "linux" package: "openmpi-doc" version: "5.0.7-1" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/MPI_Get.openmpi" --- # MPI\_Get.openmpi(3) *MPI\_Get*, *MPI\_Rget* - Copies data from the target memory to the origin. ## SYNTAX ### C Syntax ``` #include 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) 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) 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** : Initial address of origin buffer (choice). - • - **origin\_count (Number of entries in origin buffer (nonnegative)** integer). - • **origin\_datatype** : Data type of each entry in origin buffer (handle). - • **target\_rank** : Rank of target (nonnegative integer). - • - **target\_disp (Displacement from window start to the beginning of the)** target buffer (nonnegative integer). - • - **target\_count (Number of entries in target buffer (nonnegative)** integer). - • target datatype : datatype of each entry in target buffer (handle) - • **win** : window object used for communication (handle) ## OUTPUT PARAMETER - • **request** : *MPI\_Rget*: RMA request - • **ierror** : Fortran only: Error status (integer). ## DESCRIPTION *MPI\_Get* copies data from the target memory to the origin, similar to *MPI\_Put*, except that the direction of data transfer is reversed. The origin\_datatype may not specify overlapping entries in the origin buffer. The target buffer must be contained within the target window, and the copied data must fit, without truncation, in the origin buffer. Only processes within the same node can access the target window. *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. If origin\_addr points to memory attached to a window, then the data becomes available in the private copy of this window. ## 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. 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 2003-2025, The Open MPI Community