Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: %p and different pointer representations
Message-ID: <1989Mar2.173801.536@utzoo.uucp>
Organization: U of Toronto Zoology
References: <9382@bloom-beacon.MIT.EDU> <1089@vicorp.UUCP> <234@mstan.Morgan.COM> <16112@mimsy.UUCP> <9453@bloom-beacon.MIT.EDU> <1890@dataio.Data-IO.COM> <928@jhunix.HCF.JHU.EDU>
Date: Thu, 2 Mar 89 17:38:01 GMT

In article <928@jhunix.HCF.JHU.EDU> ins_balb@jhunix.UUCP (Andy Matter) writes:
>#if sizeof (void *) > sizeof (void (*)())
>#define generic_ptr (void *)
>#else
>#define generic_ptr (void (*)())
>#endif
>Then use generic_ptr instead of void *...

Unfortunately, if I recall correctly (my Oct draft is out on loan), in
strict ANSI C it is illegal to convert function pointers into object
pointers and vice-versa.  Before you scream, consider that there are
architectures on which this is not a meaningful operation, and it is
almost always a highly machine-specific operation.  The ability to do
such conversions is mentioned under "common extensions" in the appendix.
-- 
The Earth is our mother;       |     Henry Spencer at U of Toronto Zoology
our nine months are up.        | uunet!attcan!utzoo!henry henry@zoo.toronto.edu