The DefineExternal(fn, extlib) command calls define_external with the MAPLE option and saves the result in a remember table.  The procedure used to prepare the invocation of the external routine fn is returned, optionally with the specified copyright statement cright.

Note: Saving the result of DefineExternal in a remember table is essential for the efficient operation of the external linking. Without it, the external communications must be set up every time an external routine is entered.