PROBLEM: memory leak in LIST_*, TAILQ_* man page

From: David Leppik
Date: Sun Oct 16 2005 - 20:52:41 EST


My apologies if this is the wrong mailing list; I didn't find a better one.

The man page for TAILQ_REMOVE, etc. contains the following sample code:

while (head.tqh_first != NULL)
TAILQ_REMOVE(&head, head.tqh_first, entries);

I checked /usr/include/sys/queue.h and, sure enough, TAILQ_REMOVE doesn't free
head.tqh_first. Nor should it-- this isn't Objective-C, after all. :-)

It should be something like:

while (head.tqh_first != NULL) {
np = head.tqh_first;
TAILQ_REMOVE(&head, np, entries);
free(np);
}


The same bug is repeated for all the data structures in this man page.


In this day and age of Java, C#, and Objective-C programmers, kids these days
are less likely to remember to clean up after themselves. Therefore it was
particularly jarring to find this bug. Ten years ago I might have laughed it
off. That's probably why it's been around for so long.

David
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