The CDF distribution contains an interface that allows full access to the CDF library (and hence CDFs) from within IDL. CDF's IDL interface consists of a set of functions that mirror the functions in the Standard and Internal interfaces for C and Fortran applications. CDF's IDL interface is described in Appendix B.
IDL also provides its own interface to the CDF library (as well as other data formats) that differs from CDF's IDL interface. The differences are mainly syntactic with the functionality of the two interfaces being essentially the same. IDL's documentation describes their built-in CDF interface. Another difference between the two interfaces is that CDF's IDL interface is only available on those computers that support dynamic linking. Appendix B lists the computers on which this is the case.