Detaching from a remote progam: Why does GDB retain breakpoints?

Pedro Alves
Wed Oct 8 22:24:00 GMT 2008

On Wednesday 08 October 2008 23:01:57, Anmol P. Paralkar wrote:

>   I am trying to understand the 'detach' command and need your help.
>   The documentation says:
>    "After the detach command, gdb is free to connect to another target."
>   So, why does GDB retain breakpoints after detaching from the remote target?

GDB shouldn't be leaving breakpoints installed in the target on a detach.  If it
is, it is a bug.

If you refering to breakpoints as what is listed by "info breakpoints", we just
keep them, well, that's a user interface issue.  We leave them because we can, it
can be useful.  Just like we keep breakpoint if the program just exits normally
after a "run".

>   The documentation for 'disconnect' indicates that GDB could possibly re-connect
>   to the same remote target so I can see why it makes sense to retain breakpoints
>   on a 'disconnect'. But, with a 'detach', a D-packet is sent and I suppose stubs
>   will then typically relinquish control and have the target proper take over.
>   Should'nt GDB clear out all its target related debug-state on a 'detach'?

You should be seeing GDB removing the breakpoints from the target before
you see the 'D' packet: either with `z' packets if the stub supports them,
or memory writes otherwise.  Is this what you meant?

Pedro Alves

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