MPI_GET_ADDRESS(3)				     Open MPI					MPI_GET_ADDRESS(3)

MPI_Get_address — Gets the address of a location in memory.

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>/MPI_Init_thread  <#mpi-init-thread>,
       after  MPI_Finalize  <#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	<#
       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>/MPI_Comm_spawn_multiple	<#
       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 <#mpi-abort> was called on that communicator. If called
	 on a window or file, acts as if MPI_Abort <#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	 <#mpi-comm-create-errhandler>	   then	    MPI_Comm_set_errhandler	<#
	 mpi-comm-set-errhandler>

       • MPI_File_create_errhandler	<#mpi-file-create-errhandler>	  then	   MPI_File_set_errhandler	<#
	 mpi-file-set-errhandler>

       • MPI_Session_create_errhandler	 <#mpi-session-create-errhandler>   then   MPI_Session_set_errhandler	<#
	 mpi-session-set-errhandler> or at MPI_Session_init <#mpi-session-init>

       • MPI_Win_create_errhandler	<#mpi-win-create-errhandler>	  then	    MPI_Win_set_errhandler	<#
	 mpi-win-set-errhandler>

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

       See the MPI man page <#open-mpi> for a full list of MPI error codes <#open-mpi-errors>.

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

Copyright
       2003-2026, The Open MPI Community

						   Mar 05, 2026					MPI_GET_ADDRESS(3)
