Re: Running status of a process

["Steve Graegert" <graegerts@gmail.com>]

Prasanta,

On 3/21/07, Prasanta Sadhukhan <Prasanta.Sadhukhan@sun.com> wrote:
> Hi,
>
> Can anyone point as to how can I obtain the information whether a
> non-child process is still running?

If you know the PID of the process you want to obtain the status of
use the kill(2) system call.  The second argument should be 0 (zero)
to prevent a signal from being sent to the process.  If the process
exists kill(2) returns zero, or -1 otherwise.

kill(2) can indicate various errors, but an error or EPERM usually is
an indicator that the process exists, while all others indicate that
it does not.

If you're writing for systems supporting the /proc filesystem,
checking for existence of /proc/{pid} is an alternative.

If you don't know the PID you're out of luck, unless you make use of
the /proc filesystem again, which is not portable per se.

	\Steve

--

Steve Grägert <steve@graegert.com>
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