«

Hello friends,

I'm getting a bizaare glibc error referencing free -- I malloc a
chunk of memory and then later when I try to free it is when the
program aborts. I've added some debug code to the source and find
that my pointer i get from malloc matches the one that I'm calling
free with -- and there is no possibility that have i have previously
freed the memory because there is only 1 free call in the entire
source (surrounded by debug printfs) so I don't know what is going on.
Any insight?

Thanks,
Mike

On 30 Sep, 21:03, Cyron <mdigit...@yahoo.com> wrote:
> Hello friends,
>
> I'm getting a bizaare glibc error referencing free -- I malloc a
> chunk of memory and then later when I try to free it is when the
> program aborts. I've added some debug code to the source and find
> that my pointer i get from malloc matches the one that I'm calling
> free with -- and there is no possibility that have i have previously
> freed the memory because there is only 1 free call in the entire
> source (surrounded by debug printfs) so I don't know what is going on.
> Any insight?

Are you perhaps writing to memory just outside the memory you have
allocated?

Cyron wrote, On 30/09/07 21:03:
> I'm getting a bizaare glibc error referencing free -- I malloc a
> chunk of memory and then later when I try to free it is when the
> program aborts. I've added some debug code to the source and find

<snip>

You are probably writing beyond the end or before the start of the
allocated space. If you can get the program down to a reasonably small
chunk of code that shows the problem we can take a look at it.
--
Flash Gordon

In article < om>,
Cyron <> wrote:

> I'm getting a bizaare glibc error referencing free -- I malloc a
>chunk of memory and then later when I try to free it is when the
>program aborts. I've added some debug code to the source and find
>that my pointer i get from malloc matches the one that I'm calling
>free with -- and there is no possibility that have i have previously
>freed the memory because there is only 1 free call in the entire
>source (surrounded by debug printfs) so I don't know what is going on.

You almost certainly have some kind of out-of-bounds pointer error.
Your first choice for finding such things, if you have one available,
is a memory-reference-checking tool such as valgrind. From your
reference to glibc, I assume you're using Linux, so valgrind should be
available. I find that 90% of the time it directs me straight to the
bug.

-- Richard
--
"Consideration shall be given to the need for as many as 32 characters
in some alphabets" - X3.4, 1963.