Date: Fri, 8 Jun 2001 11:49:57 +0300 From: Peter Pentchev <roam@orbitel.bg> To: John Baldwin <jhb@FreeBSD.org> Cc: hackers@FreeBSD.org Subject: Re: free() and const warnings Message-ID: <20010608114957.C19938@ringworld.oblivion.bg> In-Reply-To: <XFMail.010607102051.jhb@FreeBSD.org>; from jhb@FreeBSD.org on Thu, Jun 07, 2001 at 10:20:51AM -0700 References: <20010607195634.I724@ringworld.oblivion.bg> <XFMail.010607102051.jhb@FreeBSD.org>
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On Thu, Jun 07, 2001 at 10:20:51AM -0700, John Baldwin wrote:
>
> On 07-Jun-01 Peter Pentchev wrote:
> > On Thu, Jun 07, 2001 at 07:07:22PM +0300, Peter Pentchev wrote:
> >> Hi,
> >>
> >> Is free((void *) (size_t) ptr) the only way to free a const whatever *ptr
> >> with WARNS=2? (or more specifically, with -Wcast-qual)
> >
> > Uhm. OK. So size_t may not be enough to hold a pointer. What is it then -
> > caddr_t?
>
> uintptr_t for data pointers. In theory I think code pointers may not fit in a
> uintptr_t.
>
> free((void *)(uintptr_t)ptr) should work.
>
> Of course, this begs the question of why you are free'ing a const. :)
OK, here's a scenario:
struct validation_fun {
const char *name;
valfun *fun;
int dyn;
};
This is a structure for a set of validation functions, referenced by
name from another type of object. There are some predefined functions,
present in the code at compile-time, and hardcoded in an array, with
names given as "strings". Thus, the 'const'.
However, some of the functions may be defined at runtime, with both
name and code sent by a server. In that case, the name is a dynamically
allocated char *, which needs to be freed upon cleanup. So I have:
[cleanup function]
...
if (val->dyn)
free(val->name);
Any suggestions on how to improve the design to avoid this, if possible,
would be greatly welcome.
G'luck,
Peter
--
I am the meaning of this sentence.
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