..
  Copyright 1988-2022 Free Software Foundation, Inc.
  This is part of the GCC manual.
  For copying conditions, see the copyright.rst file.

.. _acc_is_present:

acc_is_present -- Indicate whether host variable / array is present on device.
******************************************************************************

Description
  This function indicates whether the specified host address in :samp:`{a}` and a
  length of :samp:`{len}` bytes is present on the device. In C/C++, a non-zero
  value is returned to indicate the presence of the mapped memory on the
  device. A zero is returned to indicate the memory is not mapped on the
  device.

  In Fortran, two (2) forms are supported. In the first form, :samp:`{a}` specifies
  a contiguous array section. The second form :samp:`{a}` specifies a variable or
  array element and :samp:`{len}` specifies the length in bytes. If the host
  memory is mapped to device memory, then a ``true`` is returned. Otherwise,
  a ``false`` is return to indicate the mapped memory is not present.

C/C++:
  .. list-table::

     * - *Prototype*:
       - ``int acc_is_present(h_void *a, size_t len);``

Fortran:
  .. list-table::

     * - *Interface*:
       - ``function acc_is_present(a)``
     * -
       - ``type, dimension(:[,:]...) :: a``
     * -
       - ``logical acc_is_present``
     * - *Interface*:
       - ``function acc_is_present(a, len)``
     * -
       - ``type, dimension(:[,:]...) :: a``
     * -
       - ``integer len``
     * -
       - ``logical acc_is_present``

Reference:
  :openacc:`2.6`, section
  3.2.30.