HPC Magazine - OpenACC 2.0 - The new data management features

Listing 3: Custom implementation of a present_or_copy(A[n]) using API calls.

  int A[n] ;

  ...

  /* A[0:n] may or may not be present on the device */
  int was_present ;
  was_present = acc_is_present( A , n*sizeof(int) );
  if ( !was_present ) {
    acc_copyin( A , n*sizeof(int) ) 
  }

  ...

   /* A[0:n] is now present on the device */

   ...

   if ( !was_present ) {
     acc_delete( A , n*sizeof(int) ) 
   } 

   /* A[0:n] may or may not be present on the device */

   ...