Archivi tag: bug

Guard your memory with Valgrind

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Valgrind is an apt-and-play (or rpm-and-play) tool for finding memory leaks in your sw.

I recommend using it for code-reviewing and before deploying!

Just run it agains # ls -d /tmp

# valgrind  --leak-check=full --track-origins=yes ls -d /tmp

The output is [extract]

==27666== Memcheck, a memory error detector
==27666== Command: ls -d /tmp
/tmp
==27666== HEAP SUMMARY:
==27666==     in use at exit: 12,653 bytes in 8 blocks
==27666==   total heap usage: 1,396 allocs, 1,388 frees, 77,395 bytes allocated
==27666==
==27666== 120 bytes in 1 blocks are definitely lost in loss record 7 of 8
==27666==    at 0x4024C1C: malloc (vg_replace_malloc.c:195)
==27666==    by 0x40CFACD: getdelim (in /lib/tls/i686/cmov/libc-2.10.1.so)
==27666==    by 0x405B73A: ??? (in /lib/libselinux.so.1)
==27666==    by 0x4064BFC: ??? (in /lib/libselinux.so.1)
==27666==    by 0x40530C7: ??? (in /lib/libselinux.so.1)
==27666==    by 0x400D8BB: ??? (in /lib/ld-2.10.1.so)
==27666==    by 0x400DA20: ??? (in /lib/ld-2.10.1.so)
==27666==    by 0x400088E: ??? (in /lib/ld-2.10.1.so)
==27666==
==27666== LEAK SUMMARY:
==27666==    definitely lost: 120 bytes in 1 blocks
==27666==    indirectly lost: 0 bytes in 0 blocks
==27666==      possibly lost: 0 bytes in 0 blocks
==27666==    still reachable: 12,533 bytes in 7 blocks
==27666==         suppressed: 0 bytes in 0 blocks
==27666== Reachable blocks (those to which a pointer was found) are not shown.
==27666== To see them, rerun with: --leak-check=full --show-reachable=yes
==27666==
==27666== For counts of detected and suppressed errors, rerun with: -v
==27666== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 25 from 8)


Funnily we found ONE leak ;)

==27666== LEAK SUMMARY:
==27666==    definitely lost: 120 bytes in 1 blocks
==27666==    indirectly lost: 0 bytes in 0 blocks

ad it’s in

==27666== 120 bytes in 1 blocks are definitely lost in loss record 7 of 8
==27666==    at 0x4024C1C: malloc (vg_replace_malloc.c:195)
==27666==    by 0x40CFACD: getdelim (in /lib/tls/i686/cmov/libc-2.10.1.so)
==27666==    by 0x405B73A: ??? (in /lib/libselinux.so.1)
...
==27666==    by 0x400088E: ??? (in /lib/ld-2.10.1.so)

but this time we shouldn’t care too much: ls is a one-shot command!

Comments welcome!

Javascript: setattribute bug

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In javascript fare setattribute sugli elementi del dom, non setta correttamente le proprietà su tutti i browser.

A tal scopo ho fatto una piccola (MA UTILISSIMA) raccolta su quali property andrebbe usato il setAttribute mentre mostra l’alternativa sugli altri:

Attributi Cosa fare
class obj.className=”
value obj.value=”
for obj.setAttribute(‘htmlFor’,”)
colspan obj.setAttribute(‘colSpan’,”)
id obj.id=”
type obj.setAttribute(‘type’,”)
name obj.name=
size obj.setAttribute(‘size’,”)
title obj.setAttribute(‘title’,”)
tabindex obj.setAttribute(‘tabIndex’,”)
onclick ed altri eventi obj.onclick = function f(){g(parametri_di_g);};

checked (del check)  check.checked = true; (NOTA FUNZIONA SOLO DOPO
averlo appeso al dom)

Per quelli non elencati dovrebbe essere valido il setAttribute.

Per ulteriori info visitare http://webbugtrack.blogspot.com/2007/08/checkedbug-242-setattribute-doesnt-always-work.html