Re: [Fwd: dereferencing void *]

[Joël Krähemann <joel weedlight ch>]

On Mon, 2014-03-24 at 02:43 +0100, Colomban Wendling wrote:
> Le 24/03/2014 01:36, Joël Krähemann a écrit :
> > [...]
> >
> > The following will compile but is it still correct?
> >
> >   g_atomic_pointer_set(&(returnable_thread->safe_data),
> >                        NULL);
>
> Yes, as the atomic_int* functions expect a pointer to the integer to
> atomically set, the atomic_pointer* ones expect a pointer to the pointer
> to atomically set.
>
> Cheers,
> Colomban
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> https://mail.gnome.org/mailman/listinfo/gtk-app-devel-list

Thank you very much but g_atomic_pointer_set doesn't help me in this
case. It still crashes with:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffddffb700 (LWP 25872)]
ags_task_thread_append_task_queue (thread=0x97a010)
at ./src/ags/thread/ags_task_thread.c:266
266       task_thread = append->task_thread;
(gdb) bt
#0  ags_task_thread_append_task_queue (thread=0x97a010)
at ./src/ags/thread/ags_task_thread.c:266
#1  0x00007ffff4bca2df in ?? ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#2  0x00007ffff4be2df8 in g_signal_emit_valist ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#3  0x00007ffff4be3a52 in g_signal_emit ()
from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#4  0x00000000004aec46 in ags_thread_run (thread=0x97a010)
at ./src/ags/thread/ags_thread.c:1718
#5  0x00000000004aefd7 in ags_thread_loop (ptr=<optimized out>)
at ./src/ags/thread/ags_thread.c:1641
#6  0x00007ffff377a062 in start_thread (arg=0x7fffddffb700) at
pthread_create.c:312
#7  0x00007ffff34aea3d in clone ()
at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111


Here's what it does any idea why?


void
ags_task_thread_append_tasks_queue(AgsThread *thread)
{
  AgsTask *task;
  AgsTaskThread *task_thread;
  AgsTaskThreadAppend *append;
  GList *list;
  gboolean initial_wait;
  int ret;

  append = (AgsTaskThreadAppend *)
g_atomic_pointer_get(&(AGS_RETURNABLE_THREAD(thread)->safe_data));

  task_thread = append->task_thread;
  list = (GList *) append->data;

  free(append);

  /* lock */
  pthread_mutex_lock(&(task_thread->read_mutex));

  /* append to queue */
  task_thread->queued += g_list_length(list);

  task_thread->queue = g_list_concat(task_thread->queue, list);

  /*  */
  pthread_mutex_unlock(&(task_thread->read_mutex));

  /* give back to pool */
  ags_thread_stop(thread);
}


void
ags_task_thread_append_tasks(AgsTaskThread *task_thread, GList *list)
{
  AgsTaskThreadAppend *append;
  AgsThread *thread;

  g_message("tasks\0");

  append = (AgsTaskThreadAppend *) malloc(sizeof(AgsTaskThreadAppend));

  append->task_thread = task_thread;
  append->data = list;

  thread = ags_thread_pool_pull(task_thread->thread_pool);

  g_atomic_pointer_set(&(AGS_RETURNABLE_THREAD(thread)->safe_data),
                       append);

  ags_thread_lock(thread);
  AGS_THREAD_GET_CLASS(thread)->run =
ags_task_thread_append_tasks_queue;
  ags_thread_lock(thread);

  ags_thread_start(thread);
}