Path: utzoo!mnetor!uunet!husc6!hao!oddjob!gargoyle!ihnp4!homxb!mtuxo!mtune!codas!ateng!chip
From: chip@ateng.UUCP (Chip Salzenberg)
Newsgroups: comp.lang.c
Subject: Re: Variable function names
Message-ID: <130@ateng.UUCP>
Date: 21 Dec 87 18:54:57 GMT
References: <973@russell.STANFORD.EDU> <47000027@uxe.cso.uiuc.edu>
Reply-To: chip@ateng.UUCP (Chip Salzenberg)
Organization: A T Engineering, Tampa, FL
Lines: 27

In article <47000027@uxe.cso.uiuc.edu> mcdonald@uxe.cso.uiuc.edu writes:
>>[Re generating code at runtime: (*(int (*)())&array[0])()]
>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.

The iAPX 286 can't do this in protected mode, which is the only useful
mode for multitasking OS's.  (Executable segments are not writable.)

Look, if you're on a machine where executing data is allowed, you can just
cast the data address to a function pointer and call the result:

	int (*func)();
	char array[100];
	...
	func = (int (*)()) array;
	(*func)();

And if the C compiler won't even do the cast, use a union.  As they say in
Rome:  Non perspiratum ("no sweat").

-- 
Chip Salzenberg         "chip@ateng.UUCP"  or  "{codas,uunet}!ateng!chip"
A T Engineering         My employer's opinions are not mine, but these are.
 "Gentlemen, your work today has been outstanding, and I intend to recommend
    you all for promotion -- in whatever fleet we end up serving."   - JTK