Re: [squid-users] how to use XMALLOC_TRACE and XMALLOC_DEBUG

From: Henrik Nordstrom <hno@dont-contact.us>
Date: 21 Mar 2003 18:33:24 +0100

safe_free(s) sets s to NULL when it is being freed.

xfree(s) does not, and s continues to point to the freed data. Any uses
of s after this will cause memory corruption, and will be detected very
easily by a malloc debugger such as valgrind.

Regards
Henrik

fre 2003-03-21 klockan 16.41 skrev Mihalis Tsoukalos:
> So, if I want to simplify the following xfree
>
> void
> xfree(void *s)
> {
> #if XMALLOC_TRACE
> xmalloc_show_trace(s, -1);
> #endif
>
> #if XMALLOC_DEBUG
> if (s != NULL)
> check_free(s);
> #endif
> if (s != NULL)
> free(s);
> #if MEM_GEN_TRACE
> if (tracefp && s)
> fprintf(tracefp, "f:%p\n", s);
> #endif
> }
>
> could I rewrite it like that?:
>
> void xfree(void *s)
> {
> if (s != NULL)
> free(s);
> }
>
> Another question is: if after free(s), is (s == NULL) true?
>
> TIA,
> Mihalis.
>
> ----- Original Message -----
> From: "Henrik Nordstrom" <hno@squid-cache.org>
> To: "Mihalis Tsoukalos" <ekefe@freemail.gr>
> Cc: <squid-users@squid-cache.org>
> Sent: Friday, March 21, 2003 4:42 PM
> Subject: Re: [squid-users] how to use XMALLOC_TRACE and XMALLOC_DEBUG
>
>
> > fre 2003-03-21 klockan 14.50 skrev Mihalis Tsoukalos:
> > > Dear list,
> > >
> > > I want to know how to use the XMALLOC_TRACE and XMALLOC_DEBUG features.
> That
> > > is, how to compile squid with those features.
> > > I would also like to know where (in which file) do I get the output.
> >
> > Why would you want to use these?
> >
> > See configure --help, but be warned that these are depreciated test
> > functions in the Squid source, and most likely will crash your Squid.
> >
> > --
> > Henrik Nordstrom <hno@squid-cache.org>
> > MARA Systems AB, Sweden

-- 
Henrik Nordstrom <hno@squid-cache.org>
MARA Systems AB, Sweden
Received on Fri Mar 21 2003 - 10:33:37 MST

This archive was generated by hypermail pre-2.1.9 : Tue Dec 09 2003 - 16:19:34 MST