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MPI_Status_set_elements(3) man page (version 1.8.4)

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Table of Contents

Name

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

Syntax

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
P,
MPI_Count count)

Fortran Syntax


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

C++ Syntax


#include <mpi.h>
void MPI::Status::Set_elements(const MPI::Datatype& datatype, int count
P)

Input/Output Parameter

status
Status to associate with count (status).

Input Parameters

datatype
Data type associated with count (handle).
count
Number of elements to associate with status (integer).

Output Parameter

IERROR
Fortran only: Error status (integer).

Description

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

A subsequent call to MPI_Get_count(status, datatype, count), to MPI_Get_elem ents(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 M PI_Status_set_elements.

Notes

Users are advised not to reuse the status fields for values other than those for w hich 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 det ect 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 MPI_Recv, may lead to unpredictable results and is strongly discouraged.

Errors

Almost all MPI routines return an error value; C routines as the value of the func tion and Fortran routines in the last argument. C++ functions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ excepti on mechanism will be used to t hrow an MPI::Exception object.

Before the error value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job, except for I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; 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 MP I program can continue past an error.

Fortran 77 Notes

The MPI standard prescribes portable Fortran syntax for the COUNT argument o f MPI_Status_set_elements_x only for Fortran 90. FORTRAN 77 users may use the non-portable syntax


     INTEGER*MPI_COUNT_KIND COUNT

where MPI_COUNT_KIND is a constant defined in mpif.h and gives the length
of the d
eclared integer in bytes.

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