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From: "Amker.Cheng" <amker.cheng@gmail.com>
To: gdb@sourceware.org
Cc: paawan1982@yahoo.com, teawater <teawater@gmail.com>
Subject: Re: What happened in gdb between handle_sigint and  	async_request_quit?
Date: Fri, 06 Feb 2009 15:14:00 -0000	[thread overview]
Message-ID: <e8b251c80902060714k36a67d84neb5a63862430ed07@mail.gmail.com> (raw)
In-Reply-To: <e8b251c80902060114j18d0b41dn3dad9d2845df6254@mail.gmail.com>

Hi :
I think I've got the truth about what happened when CTRL+C is hit
during debugging.

both of GDB and Debuggee will get the event. Windows will report DBG_CONTROL_C
exception to GDB, which was turned into TARGET_SIGNAL_INT in GDB.
According to MSDN, this is the First Chance Exception!

Now the debugee is stopped and GDB got informed.

After I input the "continue" command .
Because the default action is nopass for SIGINT, GDB will just resume
debuggee using
function ContinueDebugEvent() with the second argument set to DBG_CONTINUE,
which stops all exception processing and continues the
thread(debuggee). That's why
debuggee will not get the CTRL+C event. To be accurate, the debuggee
has received
the CTRL+C event, just bypassed by OS violently.

Again, if I let GDB pass SIGINT to debuggee using command "handle 2 pass",
GDB will call function ContinueDebugEvent() with the second argument set to
DBG_EXCEPTION_NOT_HANDLED, which cause debuggee to continues the
exception processing(for this is a first-chance exception event).

Now I think it clear enough as how GDB handles SIGINT is concerned, am I right?
Although there are other puzzles such as the "quit_flag", etc..

Thanks for your time
Regards.


  reply	other threads:[~2009-02-06 15:14 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-05 12:31 Amker.Cheng
2009-02-05 16:13 ` teawater
2009-02-05 16:25   ` paawan oza
2009-02-06  9:14     ` Amker.Cheng
2009-02-06 15:14       ` Amker.Cheng [this message]
2009-02-06 16:43         ` Joel Brobecker
2009-02-07 10:08           ` Amker.Cheng

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