Re: [PATCH 1/2] docs: korn shells can have $? > 256 for signal-terminated children

[Stefano Lattarini]

On Thursday 29 September 2011, Peter Rosin wrote:
> Hi Stefano!
>
Hi Peter, thanks for the review.

> Some nits inlined...
> 
> Cheers,
> Peter
> 
> Stefano Lattarini wrote On 2011-09-29 10:51:
> > Some Korn shells, when a child process die due to signal number
> > n, can leave in $? an exit status of 256+n, instead of the "more
> > standard" 128+n.  See also Austin Group issue 0000051:
> >   <http://www.austingroupbugs.net/view.php?id=51>
> > 
> > * doc/autoconf.texi (Signal handling): Document the described Korn
> > Shell behaviour, and some of its possible shortcomings.
> > 
> > Suggestion by Eric Blake.
> > ---
> >  ChangeLog         |   14 +++++++----
> >  doc/autoconf.texi |   61 
> > +++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 70 insertions(+), 5 deletions(-)
> > 
> > diff --git a/ChangeLog b/ChangeLog
> > index be019f5..cb6416c 100644
> > --- a/ChangeLog
> > +++ b/ChangeLog
> > @@ -1,9 +1,13 @@
> > -2011-09-26  Eric Blake  <address@hidden>
> > -
> > -   docs: relax documentation license by dropping cover text
> > -   * doc/autoconf.texi (copying): Drop front- and back-cover texts.
> > -   * NEWS: Document this.
> > -   Reported by Brian Gough.
> > +2011-09-29  Stefano Lattarini  <address@hidden>
> > +
> > +   docs: korn shells can have $? > 256 for signal-terminated children
> > +   Some Korn shells, when a child process die due to signal number
> > +   n, can leave in $? an exit status of 256+n, instead of the "more
> > +   standard" 128+n.  See also Austin Group issue 0000051:
> 
> Perhaps more common instead of "more standard"? Once more below.
>
Yes, much better, especially since we explicitly state that the ksh
behaviour is standard w.r.t. POSIX.

> > +     <http://www.austingroupbugs.net/view.php?id=51>
> > +   * doc/autoconf.texi (Signal handling): Document the described Korn
> > +   Shell behaviour, and some of its possible shortcomings.
> > +   Suggestion by Eric Blake.
> >  
> >  2011-09-13  Stefano Lattarini  <address@hidden>
> >  
> > diff --git a/doc/autoconf.texi b/doc/autoconf.texi
> > index 91bb50a..2f74072 100644
> > --- a/doc/autoconf.texi
> > +++ b/doc/autoconf.texi
> > @@ -15610,6 +15610,67 @@ and @code{/usr/xpg4/bin/sh} will proceed to exit 
> > with status 130 (i.e.,
> >  128 + 2). In any case, if there is an active trap associated with
> >  @code{SIGINT}, those shells will correctly execute it.
> >  
> > +Some Korn shells, when a child process die due receiving a signal with
> 
> dies due to?
>
Consider this fixed.

> > +signal number @var{n}, can leave in @samp{$?} an exit status of
> > address@hidden instead of the ``more standard'' address@hidden  Observe the
> > +difference between AT&T @code{ksh93} (2011) and @code{bash} 4.1.5 on
> > +Debian:
> > +
> > address@hidden
> > +$ @kbd{/bin/ksh -c 'sh -c "kill -1 \$\$"; echo $?'}
> > +/bin/ksh: line 1: 7837: Hangup
> > +257
> > +$ @kbd{/bin/bash -c 'sh -c "kill -1 \$\$"; echo $?'}
> > +/bin/bash: line 1:  7861 Hangup        (sh -c "kill -1 \$\$")
> > +129
> > address@hidden example
> > +
> > address@hidden
> > +This @command{ksh} behaviour is allowed by POSIX, if implemented with
> > +due care; see this @uref{http://www.austingroupbugs.net/view.php?id=51,
> > +Austin Group discussion} for more background.  However, if it is not
> > +implemented with proper care, such a behaviour might can cause problems
> 
> "in" is missing here (between "problems" and "some").
> 
> and
> 
> might or can, not both :-)
>
Consider these fixed as well.

Thanks,
  Stefano