Re: emacs23.3 issues and hurd signals

[Samuel Thibault]

Svante Signell, le Thu 05 May 2011 17:02:27 +0200, a écrit :
> The latest emacs version does not compile on GNU/Hurd. When trying with
> default settings there is a segfault when compiling
> lisp/cedet/srecode/mode.el using the built emacs and dumped code.
> Changing the optimization of the C code from -O2 to -O0 resulted an
> illegal instruction at the same file, not a big improvement.

Well, that depends. Show the backtraces! :)

> he claims that single-threaded programs does not have to bother about
> the mach exception thread running in parallel to the main thread.
> 
> 1) Is this the case?

Yes: such threads do not receive signals.

> 2) Would changing the emacs code to use sigprocmask have the potential
> to make any difference here? Except making the warnings go away.

Probably not. If there's a difference between both interfaces, it means
bugs in glibc, which shall be fixed anyway.

> 3) In the man page for pthread_sigmask, there is a test example, showing
> that signals could be blocked and handled in a separate thread. However,
> when running that code in GNU/Hurd, the output is not as expected (and
> tested on GNU/Linux!).

Yes: on GNU/Hurd, there is no global sigmask, that's precisely one of
the goals of Jeremy's GSoC to fix posix-ness of GNU/Hurd signals vs
pthreads.

Samuel