example code:
-------------
#include <stdio.h>
#include <glib.h>

int main()
{
        GString *gs;
        gs=g_string_new("hello world\n");
        printf(gs->str);
        g_string_free(gs,TRUE);
        return 0;
}

You would expect no memory leaks from this code - however, valgrind -v
--show-reachable=yes --leak-check=yes ./main  will produce the following output,
which appears to be a leak within the glib library itself (2.0.0, debian-unstable)


==3537== 2172 bytes in 5 blocks are still reachable in loss record 1 of 1
==3537==    at 0x3C01F40D: malloc (vg_replace_malloc.c:105)
==3537==    by 0x3C05B161: g_malloc (in /usr/lib/libglib-2.0.so.0.200.3)
==3537==    by 0x3C05BD23: g_mem_chunk_new (in /usr/lib/libglib-2.0.so.0.200.3)
==3537==    by 0x3C069894: g_string_sized_new (in /usr/lib/libglib-2.0.so.0.200.3)
==3537==
==3537== LEAK SUMMARY:
==3537==    definitely lost: 0 bytes in 0 blocks.
==3537==    possibly lost:   0 bytes in 0 blocks.
==3537==    still reachable: 2172 bytes in 5 blocks.
==3537==         suppressed: 0 bytes in 0 blocks.