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Re: [MI] -break-insert: (a)synchronous?
- From: Keith Seitz <keiths at redhat dot com>
- To: <gdb at sources dot redhat dot com>
- Date: Thu, 13 Jun 2002 19:27:05 -0700 (PDT)
- Subject: Re: [MI] -break-insert: (a)synchronous?
On Thu, 13 Jun 2002, Andrew Cagney wrote:
> The command was implemented that way to match its documented spec. I
> remember wondering about alternate implementations at the time.
>
> Sounds like it is time to either define a new command (not capture the
> events) or change the spec.
Ok, then I would like to propose that we change the spec to use events and
only events when a command results in some event. This reduces the
redundancy.
I'm working on modifying gdbmi.texinfo, but I am a little confused about
all the stream options:
"*" = "exec-async-output"
"+" = "status-async-output"
"=" = "notify-async-output"
>From the manual ([] = my comments):
o status-async-output contains on-going status information about the
progess of slow operation. All status output is prefixed by "+".
[I presume that the biggest client for this is downloading to a target.]
o exec-async-output contains asynchronous state change on the target
(stopped, started, disappeared). All Async output is prefixed by "*".
[This seems to be called only by async target state changes.]
o notify-async-output contains supplementary information that the client
should handle (e.g., a new breakpoint information). All notify
output is prefixed by "=".
[I don't know where this is used. I am unable to find any references
to this.]
>From the descriptions above, it sounds like event notifications should
occur on the notify-async-output channel, "=".
However, if one reads down to the "Command With Side Effects" section, one
sees:
-> -symbol-file xyz.exe
<- *breakpoint,nr="3",address="0x123",source="a.c:123"
<- (gdb)
The exact meaning of this example is not really clear to me, but I
presume that it is meant to demonstrate what happens when a breakpoint is
inserted as a result of loading a new symbol file (however that may
occur). In any case, the example is certainly not exec-async-output. In
fact, it is nothing in the MI lingo.
To get the ball rolling on cleaning some of this up, I will submit a patch
which changes (replaces?) the meaning of notify-async-output to include
events in the debugger (breakpoints inserted/deleted/modified,
architecture changes, stack frame changes, switching current thread, etc),
and I will update all the examples.
If someone reads this differently than I do, please speak up.
So, here's how I interpret what should happen:
(gdb)
-break-insert main
=breakpoint-create,number="1"
^done,bkpt=...
(gdb)
(I will also be proposing that we whack the result in this case, since we
will get an event notification, too.)
Keith