Re: RFC: clear quit_flag in quit, not throw_exception

[Pedro Alves <palves@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