Many ioctl operations are common to a class of STREAMS drivers or STREAMS modules. Modules that deal with terminals usually implement a subset of the termio(7I) ioctls. Similarly, drivers that deal with audio devices usually implement a subset of the audio(7I) interfaces.
Because no data structures have changed size as a result of the LP64 data model for either termio(7I) or audio(7I), you do no need to use any of the structure macros to decode any of these ioctls.