plucky (3) MPI_Get_address.openmpi.3.gz

SYNTAX

   C Syntax
          #include <mpi.h>

          int MPI_Get_address(const void *location, MPI_Aint *address)

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'

          MPI_GET_ADDRESS(LOCATION, ADDRESS, IERROR)
              <type> LOCATION(*)
              INTEGER(KIND=MPI_ADDRESS_KIND) ADDRESS
              INTEGER IERROR

   Fortran 2008 Syntax
          USE mpi_f08

          MPI_Get_address(location, address, ierror)
              TYPE(*), DIMENSION(..), ASYNCHRONOUS :: location
              INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(OUT) :: address
              INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

       • location : Location in caller memory (choice).

OUTPUT PARAMETERS

       • address : Address of location (integer).

       • ierror : Fortran only: Error status (integer).

DESCRIPTION

       MPI_Get_address returns the byte address of a location in memory.

       Example: Using MPI_Get_address for an array.

          REAL :: A(100,100)
          INTEGER(MPI_ADDRESS_KIND) :: I1, I2, DIFF

          CALL MPI_GET_ADDRESS(A(1,1), I1, IERROR)
          CALL MPI_GET_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.

NOTES

       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_Get_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_Get_address to “reference” C variables guarantees
       portability to such machines as well.

       Current Fortran MPI codes will run unmodified and will port to any system.  However,  they  may  fail  if
       addresses  larger than 2^32 - 1 are used in the program. New codes should be written so that they use the
       new functions. This provides compatibility with C and avoids errors  on  64-bit  architectures.  However,
       such  newly written codes may need to be (slightly) rewritten to port to old Fortran 77 environments that
       do not support KIND declarations.

ERRORS

       Almost all MPI routines return an error value; C routines as  the  return  result  of  the  function  and
       Fortran routines in the last argument.

       Before  the  error  value  is  returned,  the current MPI error handler associated with the communication
       object (e.g., communicator, window, file) is called.  If no communication object is associated  with  the
       MPI  call,  then  the call is considered attached to MPI_COMM_SELF and will call the associated MPI error
       handler.  When  MPI_COMM_SELF  is  not  initialized   (i.e.,   before   MPI_Init/MPI_Init_thread,   after
       MPI_Finalize,  or  when using the Sessions Model exclusively) the error raises the initial error handler.
       The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF  when  using
       the  World  model,  or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/‐
       MPI_Comm_spawn_multiple.  If no other appropriate error handler has been set, then the  MPI_ERRORS_RETURN
       error  handler  is  called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all
       other MPI functions.

       Open MPI includes three predefined error handlers that can be used:

       • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

       • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When
         called  on  a  communicator,  it  acts  as if MPI_Abort was called on that communicator. If called on a
         window or file, acts as if MPI_Abort was called on a communicator containing the group of processes  in
         the corresponding window or file. If called on a session, aborts only the local process.

       • MPI_ERRORS_RETURN Returns an error code to the application.

       MPI applications can also implement their own error handlers by calling:

       • MPI_Comm_create_errhandler then MPI_Comm_set_errhandler

       • MPI_File_create_errhandler then MPI_File_set_errhandler

       • MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init

       • MPI_Win_create_errhandler then MPI_Win_set_errhandler

       Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.

       See the Error Handling section of the MPI-3.1 standard for more information.

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                                MPI_GET_ADDRESS(3)