# MPI_Rget

Get data from a memory window on a remote process

## Synopsis

    int 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)

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

## Input Parameters

origin_count
  number of entries in origin buffer (non-negative integer)
origin_datatype
  datatype of each entry in origin buffer (handle)
target_rank
  rank of target (non-negative integer)
target_disp
  displacement from window start to the beginning of the target buffer (non-negative integer)
target_count
  number of entries in target buffer (non-negative integer)
target_datatype
  datatype of each entry in target buffer (handle)
win
  window object used for communication (handle)

## Output Parameters

origin_addr
  initial address of origin buffer (choice)
request
  RMA request (handle)

## Thread and Interrupt Safety

This routine is thread-safe. This means that this routine may be safely used by multiple threads without the need for any user-provided thread locks. However, the routine is not interrupt safe. Typically, this is due to the use of memory allocation routines such as `malloc` or other non-MPICH runtime routines that are themselves not interrupt-safe.

## Notes for Fortran

All MPI routines in Fortran (except for `MPI_WTIME` and `MPI_WTICK`) have an additional argument `ierr` at the end of the argument list. `ierr` is an integer and has the same meaning as the return value of the routine in C. In Fortran, MPI routines are subroutines, and are invoked with the `call` statement.

All MPI objects (e.g., `MPI_Datatype`, `MPI_Comm`) are of type `INTEGER` in Fortran.

## Errors

All MPI routines (except `MPI_Wtime` and `MPI_Wtick`) return an error value; C routines as the value of the function and Fortran routines in the last argument. Before the value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job. The error handler may be changed with `MPI_Comm_set_errhandler` (for communicators), `MPI_File_set_errhandler` (for files), and `MPI_Win_set_errhandler` (for RMA windows). The MPI-1 routine `MPI_Errhandler_set` may be used but its use is deprecated. The predefined error handler `MPI_ERRORS_RETURN` may be used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error; however, MPI implementations will attempt to continue whenever possible.

MPI_SUCCESS
  No error; MPI routine completed successfully.

MPI_ERR_ARG
  Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., `MPI_ERR_RANK`).

MPI_ERR_BUFFER
  Invalid buffer pointer. Usually a null buffer where one is not valid.

MPI_ERR_COUNT
  Invalid count argument. Count arguments must be non-negative; a count of zero is often valid.

MPI_ERR_DISP

MPI_ERR_RANK
  Invalid source or destination rank. Ranks must be between zero and the size of the communicator minus one; ranks in a receive (`MPI_Recv`, `MPI_Irecv`, `MPI_Sendrecv`, etc.) may also be `MPI_ANY_SOURCE`.

MPI_ERR_TYPE
  Invalid datatype argument. Additionally, this error can occur if an uncommitted MPI_Datatype (see `MPI_Type_commit`) is used in a communication call.

MPI_ERR_WIN
  Invalid MPI window object

MPI_ERR_OTHER
  Other error; use `MPI_Error_string` to get more information about this error code.

## See Also

MPI_Get