Extension Future Growth (The GNU Awk User’s Guide)
From Get docs
C.5.4 Room For Future Growth
The API can later be expanded, in at least the following way:
gawkpasses an “extension id” into the extension when it first loads the extension. The extension then passes this id back to
gawkwith each function call. This mechanism allows
gawkto identify the extension calling into it, should it need to know.
Of course, as of this writing, no decisions have been made with respect to the above.