Re: Glib hashtable memory leak

[Pádraig Brady <P draigBrady com>]

Hrvoje Nikšić wrote:
> On Wed, 2008-04-30 at 15:33 +0300, Ovidiu Gheorghies wrote:
>> The following program appears to leak memory according to mtrace:
> 
> For something to be considered a memory leak, the program must
> accumulate the lost memory with each iteration of the suspected code
> segment.  Memory tracers often do not have sufficient information to
> distinguish genuine leaks from advanced allocation strategies, in which
> the library keeps extra storage around for later reuse.  In your case,
> you can convert your program to an infinite loop:
> 
> #include <glib.h>
> int main()
> {
>   GHashTable* hash_table;
>   for (;;) {
>     hash_table=g_hash_table_new(g_str_hash, g_str_equal);
>     g_hash_table_unref (hash_table);
>   }
>   return 0;
> }
> 
> If there were a leak in g_hash_table_new/unref, this program would soon
> consume large amounts of memory.  I observe that its memory stays within
> bounds, which means that it doesn't leak, despite the mtrace diagnostic.

Good tip. I always do this to quickly identify if my programs have a leak,
and then use valgrind et. al. to find where it is.

Make sure you `ulimit -v` appropriately though, as linux at least
becomes unresponsive if you do have a leak and start swapping.

Pádraig.