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>Date: Wed, 27 Sep 00 17:13:12 +1000 >From: "Simon Coulter" <shc@flybynight.com.au> > ... >I know C simplifies parameter passing by widening or promoting data types but it still >has to check the basic data type and handle it accordingly. I see no real reason why RPG >couldn't do the same. It just has more data types to handle so it has a bigger case >statement and it doesn't promote the data types. The compiler knows how much storage >each declared variable occupies, it can't be too difficult to use that information when >building the argument list. The only real difficulty is in deciding whether the >arguments occupy contiguous storage or not -- and to support the va_ macros used by >printf() it should be contiguous. > ... Simon, the problem is that RPG has too many different numeric types. What should it pass for say 3.5? RPG could adopt C's rules and only have 2 basic numeric type (integer and double-float), so 3.5 would be passed as 8F. Or it could say that 3.5 was packed(2,1), or perhaps packed(15,5), or maybe packed(30,15). Once the compiler has figured out what the passed type should be, you're right: it's easy. By the way, for those who would like to venture into the va_list territory, it IS possible to call vprintf and vsprintf with a single argument list (Jim Langston, I don't think it's possible to call printf this way though). But coding a va_list correctly is extremely difficult in RPG. (*Much* worse than doing the formatting yourself using RPG's own capability.) >>Perhaps someday, ILE will have "externally-described" procedures, and RPG >Isn't that what EXTPGM accomplishes anyway? Or did you have something else in mind? What I have in mind is the ability for a compiler to extract "prototype" information from a module or service program, similar to the way Java can extract information directly from a compiled class. Just a dream ... Barbara Morris +--- | This is the RPG/400 Mailing List! | To submit a new message, send your mail to RPG400-L@midrange.com. | To subscribe to this list send email to RPG400-L-SUB@midrange.com. | To unsubscribe from this list send email to RPG400-L-UNSUB@midrange.com. | Questions should be directed to the list owner/operator: david@midrange.com +---
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