$ valgrind --tool=memcheck --leak-check=yes --show-reachable=yes --num-callers=20   ./read-test 
==2138== Memcheck, a memory error detector
==2138== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al.
==2138== Using Valgrind-3.6.1 and LibVEX; rerun with -h for copyright info
==2138== Command: ./read-test
==2138== 
foo
foo
==2138== 
==2138== HEAP SUMMARY:
==2138==     in use at exit: 0 bytes in 0 blocks
==2138==   total heap usage: 1 allocs, 1 frees, 120 bytes allocated
==2138== 
==2138== All heap blocks were freed -- no leaks are possible
==2138== 
==2138== For counts of detected and suppressed errors, rerun with: -v
==2138== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 11 from 6)