Jared, do you have a script (not an interactive shell mode test case) which reproduces this problem?
Olga On Mon, Apr 5, 2010 at 8:19 PM, Jared Hudson <[email protected]> wrote: > He meant oops 0, oops 177. > > Depending on the system it can take several iterations before the > problem demonstrates itself. I would recommend trying a higher sequence > than 200 if the problem does not occur immediately. > > treasure:~ # ksh > treasure:/root # echo ${.sh.version} > Version JM 93t+ 2010-02-14 > treasure:/root # let n=0; for d in $(seq 1 10000); do if echo foo | grep > bar; then echo oops $((n++)); fi; done > treasure:/root # trap "" CHLD > treasure:/root # let n=0; for d in $(seq 1 10000); do if echo foo | grep > bar; then echo oops $((n++)); fi; done > oops 0 > oops 1 > treasure:/root # > > -- > Jared H. Hudson > Dedicated Support Engineer > [email protected] > 479-657-4309 Office > 479-283-4677 Cellular > > On Mon, 2010-04-05 at 14:03 -0400, Glenn Fowler wrote: >> what in the example code prints "bang"? >> >> On Mon, 29 Mar 2010 11:08:37 +0200 Dr. Werner Fink wrote: >> > I've just become owner of a bug report reporting a flaky behaviour >> > in handling traps on SIGCHLD. For a simply test see >> >> > ksh> echo ${sh.version} >> > Version JM 93t+ 2010-02-14 >> > ksh> trap "" CHLD >> > let n=0; for d in $(seq 1 200); do if echo foo | grep bar; then echo oops >> > $((n++)); fi; done >> > bang 0 >> > [...] >> > bang 177 >> > ksh> >> >> > and repeating the loop results in different numbers of reports >> > showing that there is a race as there should no report at all. >> >> > Beside this setting the trap to something not empty works like >> >> > ksh> trap ";" CHLD >> > let n=0; for d in $(seq 1 200); do if echo foo | grep bar; then echo oops >> > $((n++)); fi; done >> > ksh> >> >> > which is very strange. It is very common to use an >> > empty string for traps used for ignoring signals, though. >> >> > Werner >> >> > -- >> > "Having a smoking section in a restaurant is like having >> > a peeing section in a swimming pool." -- Edward Burr >> > _______________________________________________ >> > ast-users mailing list >> > [email protected] >> > https://mailman.research.att.com/mailman/listinfo/ast-users > > > > > _______________________________________________ > ast-users mailing list > [email protected] > https://mailman.research.att.com/mailman/listinfo/ast-users > -- , _ _ , { \/`o;====- Olga Kryzhanovska -====;o`\/ } .----'-/`-/ [email protected] \-`\-'----. `'-..-| / Solaris/BSD//C/C++ programmer \ |-..-'` /\/\ /\/\ `--` `--` _______________________________________________ ast-users mailing list [email protected] https://mailman.research.att.com/mailman/listinfo/ast-users
