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.. _mpi_alloc_mem:
MPI_Alloc_mem
=============
.. include_body
:ref:`MPI_Alloc_mem` |mdash| Allocates a specified memory segment.
SYNTAX
------
C Syntax
^^^^^^^^
.. code-block:: c
#include <mpi.h>
int MPI_Alloc_mem(MPI_Aint size, MPI_Info info, void *baseptr)
Fortran Syntax
^^^^^^^^^^^^^^
.. code-block:: fortran
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_ALLOC_MEM(SIZE, INFO, BASEPTR, IERROR)
INTEGER INFO, IERROR
INTEGER(KIND=MPI_ADDRESS_KIND) SIZE, BASEPTR
Fortran 2008 Syntax
^^^^^^^^^^^^^^^^^^^
.. code-block:: fortran
USE mpi_f08
MPI_Alloc_mem(size, info, baseptr, ierror)
USE, INTRINSIC :: ISO_C_BINDING, ONLY
INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: size
TYPE(MPI_Info), INTENT(IN) :: info
TYPE(C_PTR), INTENT(OUT) :: baseptr
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
INPUT PARAMETERS
----------------
* ``size``: Size of memory segment in bytes (nonnegative integer).
* ``info``: Info argument (handle).
OUTPUT PARAMETERS
-----------------
* ``baseptr``: Pointer to beginning of memory segment allocated.
* ``ierror``: Fortran only: Error status (integer).
DESCRIPTION
-----------
:ref:`MPI_Alloc_mem` allocates *size* bytes of memory. The starting address of
this memory is returned in the variable *baseptr*.
C NOTES
-------
The parameter *baseptr* is of type ``void *`` to allow passing any
pointer object for this parameter. The provided argument should be a
pointer to a pointer of arbitrary type (e.g., ``void **``).
Fortran NOTES
-------------
The :ref:`MPI_Alloc_mem` calls require the use of the ``iso_c_binding`` module
for due to the use of ``TYPE(C_PTR)``.
.. code-block:: fortran
use iso_c_binding
type(c_ptr) :: alloc_ptr
integer :: size, ierr
double precision, pointer :: array(:,:)
! A 2D array of 100 elements
size = 10 * 10
call MPI_Alloc_Mem(size * 8, MPI_INFO_NULL, alloc_ptr, ierr)
! Point to the array
call c_f_pointer(alloc_ptr, array, [10, 10])
! ... use the array ...
! Free the memory, no need for the alloc_ptr
call MPI_Free_mem(array, ierr)
ERRORS
------
.. include:: ./ERRORS.rst
.. seealso::
* :ref:`MPI_Free_mem`
|
