On Dec 17, 2009, at 7:35 PM, Roger Pack wrote:

>> "EXIT" is special pseudo signal to trap program termination.
>> So, you can use it for Signal.trap, but not to invoke by
>> the name.
>=20
> Interestingly, you can send a 0
>=20
>>> Process.kill 0, 3752
> =3D> 1
>=20
> and it works as expected (after process 3752 goes away, sending 0
> results in an exception, as it should).

Sending signal 0 is a standard Unix idiom for testing for the existence =
of the target process (failure =3D> ESRCH) and/or the capability to send =
a signal to the process (failure =3D> EPERM). It never actually delivers =
a signal to the target process. =20

Gary Wright