Re: [doco/threads] document internal thread signals on gnu/linux

[Daniel Jacobowitz <drow@mvista.com>]

On Thu, Oct 23, 2003 at 09:23:03PM -0400, Michael Elizabeth Chastain wrote:
> This patch adds some doco about the existence and side effects
> of thread internal signals in GNU/Linux systems.
> 
> It should be, errr, self-documenting.  If you can't figure out
> what I'm talking about, then I need to rewrite this.
> 
> I'm motivated to write this because one of our test programs actually
> has a coding error in it, and this doco explains why the test program is
> badly written and what happens when such a program is run under gdb.
> 
> I'm looking for two kinds of comments: (1) is the content okay,
> and (2) is the formatting okay.

Close, but not quite.

It's not extra signals that are the problem.  The thread library
(nowadays!) generates no more signals under GDB than otherwise, but it
does generate a lot of signals.  GDB knows how to ignore them.

However, at some events the thread library calls a function where GDB
puts a breakpoint.  This causes GDB to stop all threads.

Gdbserver does not suffer from this problem with such severity.  I hope
to free GDB from it eventually also, but the internals have a long way
to go first.

It can still happen if you stop the program for another reason, of
course, like a normal breakpoint.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer