On Fri, Mar 15, 2013 at 4:15 PM, Alan Somers <[email protected]> wrote:
> Thanks for the quick replies everyone.  It sounds like "kill -l" is the best 
> portable way to deal with signals' exit statuses.  I never saw the Rationale 
> section of the standard.  I wonder if the standard was influenced by ksh here?

No, the behaviour of the old Bourne shell (bsh) was dumb. It assumed
that of the 8 bits allowed by UNIX only 7 bits are used and the 8th
bit can be used to reflect signal return codes. The POSIX and SUS
standards could not (unfortunately) disallow the legacy behaviour of
128+signal number used by bsh but could *recommend* a better solution,
which is to add 256+signal number.

The real *crime* is that the legacy behaviour is continued in modern
shells like bash or dash. Please blame those authors for violating a
standard *recommendation*.

Irek
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