[lldb-dev] Debugging a running process with lldb

Matthew Gardiner mg11 at csr.com
Wed May 14 22:29:37 PDT 2014

Greg Clayton wrote:
> If we launch a process and hookup a pty to its stdin/out/err, then we shouldn't get a prompt.
Sorry, I don't understand this. Surely if we attach the inferior's (i.e. 
what you termed the process) standard IOs to a pty, then we *will* get a 
prompt, since then lldb can use it's terminal with no corruption from 
the inferiors in/out?

(I'm not actually clear about the relationship between the "process 
launch" -t and -n commands. I do accept that they are mutually 
exclusive. I assume, -n means that the stdin/out/err of the inferior is 
closed, so that lldb has complete use of the foreground, so it could use 
it's prompt. I assume -t means attach the inferior to a different pty, 
so again, lldb should still be able to use it's prompt.)
>   It is probably a bug where if you launch with --no-stdio that the LLDB prompt isn't always active.
> For attach, we will always have a prompt.
> So seems this is a bug that --no-stdio is still pushing a Process IOHandler and taking over the console while the process is running.
So you are saying if I do
(lldb) process launch -s --no-stdio
(lldb) process continue

then I should always see:
back on my terminal?

Todd, could you try this (a couple of times, in case I'm seeing 
something intermittent) please, to see if your observations agree?


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