MPI_GET_COUNT, MPI_Get_count

Purpose

Returns the number of elements in a message.

C synopsis

#include <mpi.h>
int MPI_Get_count(MPI_Status *status,MPI_Datatype datatype,
    int *count);

C++ synopsis

#include mpi.h
int MPI::Status::Get_count(const MPI::Datatype& datatype) const;

FORTRAN synopsis

include 'mpif.h' or use mpi
MPI_GET_COUNT(INTEGER STATUS(MPI_STATUS_SIZE),INTEGER DATATYPE,
    INTEGER COUNT,INTEGER IERROR)

Parameters

status
     is a status object (Status) (IN). Note that in FORTRAN a single status
     object is an array of integers.

datatype
     is the datatype of each message element (handle) (IN)

count
     is the number of elements (integer) (OUT)

IERROR
     is the FORTRAN return code. It is always the last argument.

Description

This subroutine returns the number of elements in a message. The datatype
argument and the argument provided by the call that set the status variable
should match.

When one of the MPI wait or test calls returns status for a non-blocking
operation request and the corresponding blocking operation does not provide
a status argument, the status from this wait or test call does not contain
meaningful source, tag, or message size information.

Errors

Invalid datatype

Type not committed

MPI not initialized

MPI already finalized

Related information

     MPI_IRECV
     MPI_PROBE
     MPI_RECV