DeinoMPI

The Great and Terrible implementation of MPI-2

function index

MPI_Get_address

Get the address of a location in memory
int MPI_Get_address(
  void *location,
  MPI_Aint *address
);

Parameters

location
[in] location in caller memory (choice)
address
[out] address of location (address)

Remarks

This routine is provided for both the Fortran and C programmers. On many systems, the address returned by this routine will be the same as produced by the C & operator, but this is not required in C and may not be true of systems with word- rather than byte-oriented instructions or systems with segmented address spaces.

This routine should be used instead of MPI_Address.

Thread and Interrupt Safety

This routine is both thread- and interrupt-safe. This means that this routine may safely be used by multiple threads and from within a signal handler.

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 guarentee 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_OTHER
Other error; use MPI_Error_string to get more information about this error code.

Example Code

The following sample code illustrates MPI_Get_address.

#include "mpi.h"
#include <stdio.h>

int main( int argc, char *argv[] )
{
    int errs = 0;
   
int buf[10];
    MPI_Aint a1, a2;

    MPI_Init( &argc, &argv );

    MPI_Get_address( &buf[0], &a1 );
    MPI_Get_address( &buf[1], &a2 );

   
if ((int)(a2-a1) != sizeof(int)) {
        errs++;
        printf( "Get address of two address did not return values the correct distance apart\n" );fflush(stdout);
    }
    MPI_Finalize();
   
return 0;
}