MPI_Get_count

Gets the number of "top level" elements

Synopsis


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

Input Parameters

status - return status of receive operation (Status)
datatype - datatype of each receive buffer element (handle)

Output Parameter

count - number of received elements (integer)

Notes

If the size of the datatype is zero, this routine will return a count of zero. If the amount of data in status is not an exact multiple of the size of datatype (so that count would not be integral), a count of MPI_UNDEFINED is returned instead.

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_Errhandler_set; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue past an error.

MPI_SUCCESS - No error; MPI routine completed successfully.
MPI_ERR_TYPE - Invalid datatype argument. May be an uncommitted
MPI_Datatype (see MPI_Type_commit).

Location:getcount.c