First, I tried Valgrind tool using the following command:
valgrind --tool=memcheck --leak-check=yes ./app
With some large QT application started for some short period I got the following output:
==7090== HEAP SUMMARY:
==7090== in use at exit: 5,623,365 bytes in 36,268 blocks
==7090== total heap usage: 32,454,680 allocs, 32,418,412 frees, 12,822,939,874 bytes allocated
................................
==7090== LEAK SUMMARY:
==7090== definitely lost: 20,163 bytes in 74 blocks
==7090== indirectly lost: 60,053 bytes in 1,273 blocks
==7090== possibly lost: 396,167 bytes in 2,169 blocks
==7090== still reachable: 4,834,822 bytes in 31,576 blocks
==7090== suppressed: 0 bytes in 0 blocks
==7090== Reachable blocks (those to which a pointer was found) are not shown.
==7090== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==7090==
==7090== For counts of detected and suppressed errors, rerun with: -v
==7090== Use --track-origins=yes to see where uninitialised values come from
==7090== ERROR SUMMARY: 20905 errors from 1583 contexts (suppressed: 15 from 2)