Path: utzoo!mnetor!uunet!husc6!cmcl2!rutgers!iuvax!pur-ee!uiucdcs!uxc.cso.uiuc.edu!uxe.cso.uiuc.edu!mcdonald
From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.lang.c
Subject: Re: Variable function names
Message-ID: <47000027@uxe.cso.uiuc.edu>
Date: 18 Dec 87 15:33:00 GMT
References: <973@russell.STANFORD.EDU>
Lines: 40
Nf-ID: #R:russell.STANFORD.EDU:973:uxe.cso.uiuc.edu:47000027:000:1713
Nf-From: uxe.cso.uiuc.edu!mcdonald    Dec 18 09:33:00 1987


me:
>[Re generating code at runtime: (*(int (*)())&array[0])()]
>I have since learned that on some systems ... it won't work, and that ANSI C
>does not require it to work (A FATAL FLAW). BUT, on all the machines that I
>regularly use ... it does work

Karl W. Z. Heuer:

So, it's a FATAL FLAW that ANSI C has to work on machines other than the ones
you regularly use?  Gimme a break.

Me again:

Yes, I really mean it. I can't see why it cannot be specified to be generally
useful. I realize that, somewhere, there might be a machine that CAN'T,
realy, truly CAN'T, do what I want, but I have never seen one described to 
me. There are machines where the architecture or the operating system
makes it hard, or not the default, but not impossible. The language 
specifiers should put it in the language. Then, if a particular machine
simply can't do it,  their C compiler would be sold with an asterisk *


* due to the stupid blunder we made when we decided on this machine's 
architecture, it is impossible for us allow you to write an incremental
compiler. Therefore, we are unable to produce a completely implemented
compiler. So sorry.


By fatal flaw, I mean that it is fatal to my programs. A substantial
fraction of the programs I have written for the IBM-PC are in fact
dependent on being incremental compilers. It is also fatal to the claim
that C is a general purpose language. It wouldn't matter in special-
purpose languages like Fortran or Cobol. Again, I would be perfectly
happy if you had to declare specifically that you wanted code and
data to be co-accessible. Could you give me an example of a machine
where this would be impossible? (perhaps some hard-wired Lisp processor
?)

Doug McDonald