Pour obtenir une clé
d'essai remplissez le formulaire ci-dessous
Demandez des tariffs
Nouvelle licence
Renouvellement de licence
--Sélectionnez la devise--
USD
EUR
RUB
* En cliquant sur ce bouton, vous acceptez notre politique de confidentialité

Free PVS-Studio license for Microsoft MVP specialists
To get the licence for your open-source project, please fill out this form
** En cliquant sur ce bouton, vous acceptez notre politique de confidentialité.

I am interested to try it on the platforms:
** En cliquant sur ce bouton, vous acceptez notre politique de confidentialité.

Votre message a été envoyé.

Nous vous répondrons à


Si vous n'avez toujours pas reçu de réponse, vérifiez votre dossier
Spam/Junk et cliquez sur le bouton "Not Spam".
De cette façon, vous ne manquerez la réponse de notre équipe.

>
>
>
Issues of 64-bit code in real programs:…

Issues of 64-bit code in real programs: qsort

11 Jan 2010
Author:

We continue the cycle of posts about 64-bit errors detected in real applications. Time passes, demands for memory being consumed grow more and more, and now the time has come when somebody decides to sort an array consisting of more than 2^31 items. For that purpose this person chooses the function qsort implemented in OpenBSD 4.5. The result is a 64-bit error detected.

Let us consider this error in detail. At the moment of writing this post, the last revision of the file "lib/libc/stdlib/qsort.c" included into OpenBSD 4.6. dates back to August, 2005. There, the function qsort employs the auxiliary variables "d" and "r" that have the type int:

void
qsort(void *aa, size_t n, size_t es,
  int (*cmp)(const void *, const void *))
{
  char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
  int d, r, swaptype, swap_cnt;
  char *a = aa;
  . . . .

You may see the full text of the function here.

These variables are used to store different sizes and it leads to errors when processing a large number of items. The correction lies in declaring these variables as size_t:

size_t d, r;

This error is exemplary because it was detected only in 2010! It seems that a large number of errors in 64-bit programs will begin to occur when a standard user computer has more than 16 Gbytes of memory and programs begin to exploit it very actively.

Comments (0)

Next comments
Unicorn with delicious cookie
Nous utilisons des cookies pour améliorer votre expérience de navigation. En savoir plus
Accepter