On Fri, 9 Jun 2017 11:50:39 -0700, Charles Mills wrote: >I know what XPLINK means. Is XPLINK a standard? Then is XPLINK linkage >non-standard? That was my "whatever that means." Is XPLINK a standard for >non-standard linkage?
Well, I suppose you could say that XPLINK is a standard, but IMO that only adds to the confusion. When I started programming in 1970, the standard linkage conventions were already well established. Programs that follow the standard linkage conventions don't have to provide detailed specifications for how to call them. And as an additional benefit, when the system prints a dump, the save areas can be formatted so that calling sequences can be determined. There is nothing to stop a programmer from writing a program that specifies different requirements for being called. Especially in the early days, it might have been tempting to do so, but that adds to the burden when documenting the interface. You won't get any help from the system in determine what program called the one that abended when you get a dump though. For many years, this convention was called "standard linkage" to distinguish from requirements that a program might establish for itself. Then, somewhere around 2000, XPLINK was invented for the benefit of C programs. I'm not thrilled with the term, "standard linkage" for reasons similar to what you are asking. Unfortunately, we don't have another name for it, so I continue to call it by that name. -- Tom Marchant
