Require /bin/sh support XSI extensions for kill and trap

Due to the widespread use of these extensions by scripts already in
the archive, require that /bin/sh support the XSI extensions for kill
and trap which permit kill -<signal> and use of numeric signals for
well-known signals.  Also permit trapping of SIGPIPE by signal number,
since this is done by well-known portable shell scripts like libtool.

diff --git a/policy.sgml b/policy.sgml
index bad28af4257fb481693ce342af8a6b13fffdc4db..1658cbfded81b08e5c088d3fc39aab5a19505d31 100644 (file)
--- a/policy.sgml
+++ b/policy.sgml
@@ -7427,7 +7427,19 @@ fname () {
 </example>
              must be supported and must set the value of <tt>c</tt> to
              <tt>delta</tt>.
-            </item>
+           </item>
+           <item>The XSI extension to <prgn>kill</prgn> allowing <tt>kill
+             -<var>signal</var></tt>, where <var>signal</var> is either
+             the name of a signal or one of the numeric signals listed in
+             the XSI extension (0, 1, 2, 3, 6, 9, 14, and 15), must be
+             supported.
+           </item>
+           <item>The XSI extension to <prgn>trap</prgn> allowing numeric
+             symbols must be supported.  However, only the signal numbers
+             listed in the extension, which are the same as
+             for <prgn>kill</prgn> above, plus SIGPIPE (13) must be
+             supported.
+           </item>
          </list>
          If a shell script requires non-SUSv3 features from the shell
          interpreter other than those listed above, the appropriate shell