These access routines allow you to get a native Fortran data type containing exactly the information you want, i.e., the size of the mxArray, whether or not it is a string, or its data contents. This is inconvenient for many applications, as it means that the program may have to be recompiled before it can be run with a different problem size. Many operating environments let the user allocate contiguous blocks of memory whose sizes are determined at run time.
Most scientific programs involve large amounts of data that the programmer is called upon to manage.
If space is a problem, and it often is, using space efficiently becomes important. A pointer facility makes it possible to do this with efficiency and clarity. A pointer facility is also included in the Fortran 90 standard. However, Cray pointers are not like Fortran 90 pointers. While converting from Cray pointers to Fortran 90 pointers is possible, you will have to modify your existing programs to conform with the Fortran 90 standard.