Red Hat Bugzilla – Bug 429559
Man page of "kill(1)" is missing a description of "kill -0" (and so does bash)
Last modified: 2008-07-24 16:01:45 EDT
The "kill -0 $pid" (kill ZERO) option is apparently not to send a signal to
some process but to test whether the process is alive.
A quick look at the source code of kill(1) shows that if 0 is given as signal
number, the kill(2) system call is performed with 0 (simple passthrough). The
man page of kill(2) says "If sig is 0, then no signal is sent, but error
checking is still performed."
--> So, a remark to that effect should be in the kill(1) manpage.
Note that the called "kill" will probably rarely be "/bin/kill" but instead the
bash-builtin "kill". The bash manpage has the same problem as described.
Fixed in util-linux-ng upstream code. Thanks for your report.
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An advisory has been issued which should help the problem
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