Given a PID ( suppose 1356) . How do i tell if its running or not
It would be really helpful if you could explain me ..
I got this answer from google but i am unable to understand it
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Use kill() with 0 for the signal number.
There are four possible results from this call:
kill() returns 0
this implies that a process exists with the given PID, and the system
would allow you to send signals to it. It is system-dependent whether
the process could be a zombie.
kill() returns @math{-1}, errno == ESRCH
either no process exists with the given PID, or security enhancements
are causing the system to deny its existence. (On some systems, the
process could be a zombie.)
kill() returns @math{-1}, errno == EPERM
the system would not allow you to kill the specified process. This
means that either the process exists (again, it could be a zombie) or
draconian security enhancements are present (e.g. your process is not
allowed to send signals to anybody).
kill() returns @math{-1}, with some other value of errno
you are in trouble!
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