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Re: RFC: clear quit_flag in quit, not throw_exception
- From: Pedro Alves <palves at redhat dot com>
- To: Tom Tromey <tromey at redhat dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Thu, 02 Aug 2012 18:09:00 +0100
- Subject: Re: RFC: clear quit_flag in quit, not throw_exception
- References: <87mx2dqnk8.fsf@fleche.redhat.com>
On 08/02/2012 05:13 PM, Tom Tromey wrote:
> I noticed that throw_exception clears quit_flag and immediate_quit.
>
> This seems like it could cause gdb to miss C-c sometimes.
> In particular, if a SIGINT arrives and then, before QUIT is called, some
> code in gdb throws an unrelated exception, then the SIGINT will
> effectively be ignored.
>
> It seems to me that it is just as safe, and more correct, to clear these
> flags in the quit function.
If the unrelated exception/error unwinds things all the way up to the
top prompt, managing to bypass all QUIT calls, then we'll end up with
a dangling quit until the next command it entered (resulting in a spurious,
delayed "Quit"), it seems to me. If that analysis is correct, maybe we should
also clear or handle these somehow somewhere near the top loop?
>
> Tom
>
> * exceptions.c (throw_exception): Don't clear quit_flag or
> immediate_quit.
> * utils.c (quit): Clear quit_flag and immediate_quit.
> ---
> gdb/exceptions.c | 3 ---
> gdb/utils.c | 3 +++
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/exceptions.c b/gdb/exceptions.c
> index 7db9df9..84c21a2 100644
> --- a/gdb/exceptions.c
> +++ b/gdb/exceptions.c
> @@ -221,9 +221,6 @@ exceptions_state_mc_action_iter_1 (void)
> void
> throw_exception (struct gdb_exception exception)
> {
> - quit_flag = 0;
> - immediate_quit = 0;
> -
> do_cleanups (all_cleanups ());
>
> /* Jump to the containing catch_errors() call, communicating REASON
> diff --git a/gdb/utils.c b/gdb/utils.c
> index c69c3e0..6ba8c62 100644
> --- a/gdb/utils.c
> +++ b/gdb/utils.c
> @@ -1055,6 +1055,9 @@ print_sys_errmsg (const char *string, int errcode)
> void
> quit (void)
> {
> + quit_flag = 0;
> + immediate_quit = 0;
> +
> #ifdef __MSDOS__
> /* No steenking SIGINT will ever be coming our way when the
> program is resumed. Don't lie. */
>
--
Pedro Alves