Mr. Metz has again betrayed his ignorance--or, perhaps better, naif understanding--of the PL/I language.
An external controlled variable is independent of the block structure of the PL/.I procedures in which it is used; and their chief uses, explicit and under the covers, are just as anchors for shared constructs like files and control blocks: a separate PRV instance is allocated and initialized for each PL/I dispatchable. It is true that for, say, declare cp pointer controlled ; . . . allocate cp ; . . . allocate cp ; second and subsequent instances of the same variable are pushed down as another instance of it is allocated and popped up/reinstated when an instance of that variable is freed, but this is incidental behavior, and no sane person would try to manage a PL/I stack by exploiting it: much simpler, lower-overhead schemes for doing so are readily implemented. John Gilmore, Ashland, MA 01721 - USA ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
