Not possible to call kill(pid, 0)

[mkollaro]

According to the man page:

If sig is 0, then no signal is sent, but error checking is still performed; this can be used to check for the existence of a process ID or process group ID.

The current signature is pub fn kill(pid: pid_t, signal: Signal), and I think it should use Option<Signal>.

[kamalmarhubi]

Thanks for the report. This is being handled in #445, which is close to done.