I just switched from gcc 2.95.x, where the GNUstep dox say I must use
gnustep-objc, to gcc 3.3 where
they say the built-in libobjc works fine. But it doesn't. It leaks threads, so
eventually your program
crashes in objc_detach_thread. The reason is that in gcc's libobjc, threads are
created joinable, so when
they exit they hang around forever waiting to be joined.
In gthr-posix.h:
if (!(pthread_create (&new_thread_handle, NULL, (void *) func, arg)))
the second argument to pthread_create is NULL, which means default attributes,
which on linux 2.4 I
believe means the threads are joinable, not detached. Now it looks like someone
thought about this a
bit because in the same gthr-posix.h there is a variable called
_objc_thread_attribs initialized thusly:
/* The normal default detach state for threads is
* PTHREAD_CREATE_JOINABLE which causes threads to not die
* when you think they should. */
if (pthread_attr_init (&_objc_thread_attribs) == 0
&& pthread_attr_setdetachstate (&_objc_thread_attribs,
PTHREAD_CREATE_DETACHED) == 0)
return 0;
but _objc_thread_attribs, which you would think would be used as
pthread_create's second argument, is
in fact never used at all!
Note that the thr-posix.c in gnustep-objc has nearly identical code that works
-- it remembers to pass
the _objc_thread_attribs in:
if (!(pthread_create(&new_thread_handle, &_objc_thread_attribs,
(void *)func, arg)))
--
Summary: libobjc leaks threads on posix
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: libobjc
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: lcampbel at akamai dot com
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19850
