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This is a followup to a report back in 2011 about essentially the same issue: https://cygwin.com/ml/cygwin/2011-04/msg00031.html The same test program in that report demonstrates the issue, but with kill sending any non-zero signal. To reiterate, the problem here is POSIX compliance with respect to sending signals to zombie processes. http://pubs.opengroup.org/onlinepubs/9699919799/functions/kill.html claims: Existing implementations vary on the result of a kill() with pid indicating an inactive process (a terminated process that has not been waited for by its parent). Some indicate success on such a call (subject to permission checking), while others give an error of [ESRCH]. Since the definition of process lifetime in this volume of POSIX.1-2008 covers inactive processes, the [ESRCH] error as described is inappropriate in this case. In particular, this means that an application cannot have a parent process check for termination of a particular child with kill(). (Usually this is done with the null signal; this can be done reliably with waitpid().) In response to the originally issue, this was fixed *specifically* for the case of kill(pid, 0). But my reading of the above is that kill() should return 0 in this case regardless of the signal (modulo permissions, etc.). On Linux, for example, when calling kill with pid of a zombie process the kernel will happily deliver the signal to the relevant task_struct; it will just never be acted on since the task will never run again. Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.