Manpages - MPI_Address.3

MPI_Address - Gets the address of a location in memory – use of this routine is deprecated.

  #include <mpi.h>
  int MPI_Address(void *location, MPI_Aint *address)

  INCLUDE 'mpif.h'
  MPI_ADDRESS(LOCATION, ADDRESS, IERROR)
  	<type>	LOCATION (*)
  	INTEGER	ADDRESS, IERROR

location

Location in caller memory (choice).

address

Address of location (integer).

IERROR

Fortran only: Error status (integer).

Note that use of this routine is deprecated as of MPI-2. Please use MPI_Get_address instead.

This deprecated routine is not available in C++.

The address of a location in memory can be found by invoking this function. Returns the (byte) address of location.

Example: Using MPI_Address for an array.

  REAL A(100,100)

INTEGER I1, I2, DIFF
CALL MPI_ADDRESS(A(1,1), I1, IERROR)
CALL MPI_ADDRESS(A(10,10), I2, IERROR)
DIFF = I2 - I1
! The value of DIFF is 909*sizeofreal; the values of I1 and I2 are
! implementation dependent.

This routine is provided for both Fortran and C programmers and may be useful when writing portable code. In the current release, the address returned by this routine will be the same as that produced by the C & operator.

C users may be tempted to avoid using MPI_Address and rely on the availability of the address operator &. Note, however, that & cast-expression is a pointer, not an address. ANSI C does not require that the value of a pointer (or the pointer cast to int) be the absolute address of the object pointed at although this is commonly the case. Furthermore, referencing may not have a unique definition on machines with a segmented address space. The use of MPI_Address to “reference” C variables guarantees portability to such machines as well.

Almost all MPI routines return an error value; C routines as the value of the function 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++ exception mechanism will be used to throw 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 MPI program can continue past an error.

MPI_Get_address