The getPDFcontext operator
This page applies to Harlequin v13.1r0 and later; and to Harlequin Core but not Harlequin MultiRIP.
file getPDFcontext int
This operator is defined in internaldict.
Expects a file object on the stack and returns the associated PDF context ID, or 0
(zero) if there is no context, meaning that the stream is not a PDF stream. (In other words, no context means that the file is a PostScript-language job.)