Re: questions / suggestions about gdb

["Charles James Leonardo Quarra Cappiello" <charsquarra@hotmail.com>]

Andrew Cagney wrote:

>
>>Daniel Jacobowitz wrote:
>>
>>
>>>can i activate the 'generate-core-file' a few steps before the program
>>>breaks?
>>
>>Whenever you want to; you just issue the command, and then you can come
>>back to look at the core file later.
>>
>>
>>my question is; how the debugger would automatically know that three steps 
>>further the program will break and generate a core file; i guess to 
>>generate core files on every (say, 100 steps) could help a lot too.
>
>In theory .... In addition to saving the internal state of the program,
>you'll need to record all the external state and any additional I/O that
>the running program performs.  That way you can exactly replay that
>program's behavour (this gets tricky when you're trying to to timers
>just right).  I suspect you'd end up having to use a simulator for this.
>  Alternativly, you can ignore the external state problem and get
>something working most of the time (via something like fork()?).
>
>Another possability is to have GDB use its builtin-simulator to look
>ahead a few instructions at what the inferior would do given its current
>state.  Provided the simulator doesn't modify the inferior (debugged
>process) nor do I/O it shouldn't affect the program that is running.
>
>enjoy,
>Andrew
>
>

But i still think that having two instances of the debugger with a step 
offset, in which when the one advanced in time breaks, makes the other 
behind pause, would help a lot, DDD couldn't handle this without much 
burden?


-Charles Quarra








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