Subject: Re: ptrace(2) + nathanw_sa LWPs
To: Jason R Thorpe <>
From: Giles Lean <>
List: tech-kern
Date: 12/08/2001 14:23:13
> So, I've been poking around at our debugging support lately, and I
> had remembered Nathan complaining about ptrace(2), specifically that
> it pretty much sucks when it comes to multiple LWPs.
> It seems to me that we could simply add a ptrace(2) request to "set
> which LWP this request is for".

Is it interesting to compare what other operating systems have done?
HP-UX introduced ttrace(2) to overcome the limitations of ptrace(2)
with multithreaded processes, and HP contributed changes to gdb to
enable it to use ttrace(2).

I don't know how Solaris supports debugging multithreaded processes
as its ptrace(2) manual page doesn't refer to threads at all.