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[patchv3] Sort threads for thread apply all (bt)

On Thu, 22 Jan 2015 01:26:46 +0100, Doug Evans wrote:
> Just some nits, no need to resubmit for review.

Resubmitting it as a request for doc approval from Eli.

>  > +static int tp_array_compar_asc;
> This should probably have a comment.

Done, I forgot.

>  > +
>  > +/* Sort an array for struct thread_info pointers by their ascending NUM.  */
>  > +
>  > +static int
>  > +tp_array_compar (const void *ap_voidp, const void *bp_voidp)
>  > +  return ((((*ap)->num > (*bp)->num) - ((*ap)->num < (*bp)->num))
>  > +	  * (tp_array_compar_asc ? +1 : -1));
>  > +}
> This triggers my "passing parameters as global variables" alarm,
> and while one could instead have two different functions,

I believe qsort_r() is more appropriate, using two different functions I would
feel rather as a workaround of missing qsort_r(). But I guess (I cannot easily
test due to missing slaves and no patch testing feature in Sergio's Buildbot
yet) some of the supported platforms do not provide qsort_r() so it would need
a new gdb/gnulib/ module. But at least one of my gdb/gnulib/ patches is still
under review so it would create dependency between unrelated patchsets.

>  > +  if (cmd && (check_for_argument (&cmd, "-asc", strlen ("-asc"))))
> cmd != NULL

BTW this has been copy-paste but yes, my fault, I am aware of it.

2015-01-16  Jan Kratochvil  <>

	* thread.c (tp_array_compar_ascending, tp_array_compar): New.
	(thread_apply_all_command): Parse CMD for tp_array_compar_ascending.
	Sort tp_array using tp_array_compar.
	(_initialize_thread): Extend thread_apply_all_command help.

2015-01-16  Jan Kratochvil  <>

	* gdb.texinfo (Threads): Describe -ascending for thread apply all.

diff --git a/gdb/thread.c b/gdb/thread.c
index 4bce212..870a956 100644
--- a/gdb/thread.c
+++ b/gdb/thread.c
@@ -1381,6 +1381,24 @@ make_cleanup_restore_current_thread (void)
+/* If non-zero tp_array_compar should sort in ascending order, otherwise in
+   descending order.  */
+static int tp_array_compar_ascending;
+/* Sort an array for struct thread_info pointers by their NUM, order is
+   determined by TP_ARRAY_COMPAR_ASCENDING.  */
+static int
+tp_array_compar (const void *ap_voidp, const void *bp_voidp)
+  const struct thread_info *const *ap = ap_voidp;
+  const struct thread_info *const *bp = bp_voidp;
+  return ((((*ap)->num > (*bp)->num) - ((*ap)->num < (*bp)->num))
+	  * (tp_array_compar_ascending ? +1 : -1));
 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
    of two numbers seperated by a hyphen.  Examples:
@@ -1397,6 +1415,13 @@ thread_apply_all_command (char *cmd, int from_tty)
   int tc;
   struct thread_array_cleanup ta_cleanup;
+  tp_array_compar_ascending = 0;
+  if (cmd != NULL && (check_for_argument (&cmd, "-ascending", strlen ("-asc"))))
+    {
+      cmd = skip_spaces (cmd);
+      tp_array_compar_ascending = 1;
+    }
   if (cmd == NULL || *cmd == '\000')
     error (_("Please specify a command following the thread ID list"));
@@ -1430,6 +1455,8 @@ thread_apply_all_command (char *cmd, int from_tty)
+      qsort (tp_array, i, sizeof (*tp_array), tp_array_compar);
       make_cleanup (set_thread_refcount, &ta_cleanup);
       for (k = 0; k != i; k++)
@@ -1738,7 +1765,14 @@ The new thread ID must be currently known."),
 		  &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
   add_cmd ("all", class_run, thread_apply_all_command,
-	   _("Apply a command to all threads."), &thread_apply_list);
+	   _("\
+Apply a command to all threads.\n\
+Usage: thread apply all [-ascending] <command>\n\
+-ascending: Call <command> for all threads in ascending order.\n\
+            The default is descending order.\
+	   &thread_apply_list);
   add_cmd ("name", class_run, thread_name_command,
 	   _("Set the current thread's name.\n\
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index f413e23..277df25 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -2959,14 +2959,17 @@ information on convenience variables.
 @kindex thread apply
 @cindex apply command to several threads
-@item thread apply [@var{threadno} | all] @var{command}
+@item thread apply [@var{threadno} | all [-ascending]] @var{command}
 The @code{thread apply} command allows you to apply the named
 @var{command} to one or more threads.  Specify the numbers of the
 threads that you want affected with the command argument
 @var{threadno}.  It can be a single thread number, one of the numbers
 shown in the first field of the @samp{info threads} display; or it
-could be a range of thread numbers, as in @code{2-4}.  To apply a
-command to all threads, type @kbd{thread apply all @var{command}}.
+could be a range of thread numbers, as in @code{2-4}.  To apply
+a command to all threads in descending order, type @kbd{thread apply all
+@var{command}}.  To apply a command to all threads in ascending order,
+type @kbd{thread apply all -ascending @var{command}}.
 @kindex thread name
 @cindex name a thread

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