18.2.342. MPI_Status_set_elements — Open MPI 5.0.0 documentation

# 18.2.342. MPI_Status_set_elements

MPI_Status_set_elements, MPI_Status_set_elements_x - Modifies opaque part of status to allow MPI_Get_elements to return count.

## 18.2.342.1. SYNTAX

### 18.2.342.1.1. C Syntax

    #include <mpi.h>

    int MPI_Status_set_elements(MPI_Status *status, MPI_Datatype datatype, int count)
    int MPI_Status_set_elements_x(MPI_Status *status, MPI_Datatype datatype, MPI_Count count)

### 18.2.342.1.2. Fortran Syntax

    USE MPI
    ! or the older form: INCLUDE 'mpif.h'
    MPI_STATUS_SET_ELEMENTS(STATUS, DATATYPE, COUNT, IERROR)
         INTEGER STATUS(MPI_STATUS_SIZE), DATATYPE, COUNT, IERROR
    MPI_STATUS_SET_ELEMENTS_X(STATUS, DATATYPE, COUNT, IERROR)
         INTEGER STATUS(MPI_STATUS_SIZE), DATATYPE
            INTEGER(KIND=MPI_COUNT_KIND) COUNT
            INTEGER IERROR

### 18.2.342.1.3. Fortran 2008 Syntax

    USE mpi_f08
    MPI_Status_set_elements(status, datatype, count, ierror)
         TYPE(MPI_Status), INTENT(INOUT) :: status
         TYPE(MPI_Datatype), INTENT(IN) :: datatype
         INTEGER, INTENT(IN) :: count
         INTEGER, OPTIONAL, INTENT(OUT) :: ierror
    MPI_Status_set_elements_x(status, datatype, count, ierror)
         TYPE(MPI_Status), INTENT(INOUT) :: status
         TYPE(MPI_Datatype), INTENT(IN) :: datatype
         INTEGER(KIND = MPI_COUNT_KIND), INTENT(IN) :: count
         INTEGER, OPTIONAL, INTENT(OUT) :: ierror

## 18.2.342.2. INPUT/OUTPUT PARAMETER

- `status`: Status to associate with count (status).

## 18.2.342.3. INPUT PARAMETERS

- `datatype`: Data type associated with count (handle).

- `count`: Number of elements to associate with status (integer).

## 18.2.342.4. OUTPUT PARAMETER

- `ierror`: Fortran only: Error status (integer).

## 18.2.342.5. DESCRIPTION

MPI_Status_set_elements modifies the opaque part of status so that a call to :ref:`MPI_Get_elements` or :ref:`MPI_Get_elements_x` will return count. :ref:`MPI_Get_count` will return a compatible value.

A subsequent call to MPI_Get_count(status, datatype, count), to MPI_Get_elements(status, datatype, count), or to MPI_Get_elements_x(status, datatype, count) must use a data-type argument that has the same type signature as the data-type argument that was used in the call to MPI_Status_set_elements.*

## 18.2.342.6. NOTES

Users are advised not to reuse the status fields for values other than those for which they were intended. Doing so may lead to unexpected results when using the status object. For example, calling MPI_Get_elements may cause an error if the value is out of range, or it may be impossible to detect such an error. The extra_state argument provided with a generalized request can be used to return information that does not logically belong in status. Furthermore, modifying the values in a status set internally by MPI, such as :ref:`MPI_Recv`, may lead to unpredictable results and is strongly discouraged.

## 18.2.342.7. 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.