Re: signals of type SIGSEGV handled only once (in multithreaded process)

[Samuel Thibault <samuel dot thibault at ens-lyon dot org>]

Corinna Vinschen, le Fri 15 Feb 2008 11:02:53 +0100, a écrit :
> On Feb 15 10:49, Samuel Thibault wrote:
> > Corinna Vinschen, le Fri 15 Feb 2008 10:45:47 +0100, a écrit :
> > > On Feb 15 09:37, klement2 wrote:
> > > > After excellently quick correction of pthread_kill when the argument
> > > > signal is zero
> > > > (by cgf), I have found another problem related to signal handling. The
> > > > code in attachment
> > > > demonstrates it ( because of pthread_kill, it must be run with
> > > > cygwin1-20080213.dll and newer ).
> > > > It seams that signal handlers for signals like SIGSEGV, SIGFPE are
> > > > called only once,
> > > 
> > > This patch was necessary to get SEHs (and so Cygwin) working correctly
> > > on Windows 2008 Server.  The new behaviour is covered by POSIX:
> > > 
> > > http://www.opengroup.org/onlinepubs/009695399/functions/signal.html
> > > 
> > >   "If and when the function returns, if the value of sig was SIGFPE,
> > >    SIGILL, or SIGSEGV or any other implementation-defined value
> > >    corresponding to a computational exception, the behavior is undefined.
> > >    Otherwise, the program shall resume execution at the point it was
> > >    interrupted."
> > 
> > His handler doesn't return, it calls pthread_exit(), thus killing the
> > thread causing the SIGFPE, SIGILL or SIGSEGV.
> 
> ...and then it returns.  Where to?

who returns ? "The pthread_exit() function cannot return to its caller."

Samuel

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