Signal Processing Post: 8202

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Top Forums UNIX for Dummies Questions & Answers Signal Processing Post 8202 by Perderabo on Monday 8th of October 2001 10:19:26 AM

10-08-2001

Administrator Emeritus

Gee, thanks for the kind words guys!

No, you cannot just assume the next pid will be the current pid +1. You're on a multi-user machine. Stuff like cron runs all the time. If someone else forks first, they get the next pid. Also in a multi-cpu system, each cpu will usually reserve a chunk of 10 or so pids at once to cut down on spinlocks. Finally, pids recycle after pid 32,000.

The worst consequence of the sleep program in the background is that it is consuming a proc table entry. Too many of these and eventually you bump into maxuprc and cannot fork anymore. As long as that was not an issue, I'd just let it run. Remember that it will take code to remember or find the pid and then kill the pid. The load that this code would put on the system is trivial, but the only payback is the early death of a sleep statement...it can't make a profit.

If you really got to nail that last sleep process, a "kill $(ps -f | grep [s]leep |awk '{print $2}')" should get it.

Perderabo

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explain_kill_or_die

explain_kill_or_die(3)					     Library Functions Manual					    explain_kill_or_die(3)

NAME

       explain_kill_or_die - send signal to a process and report errors

SYNOPSIS

       #include <libexplain/kill.h>
       void explain_kill_or_die(pid_t pid, int sig);
       int explain_kill_on_error(pid_t pid, int sig);

DESCRIPTION

       The  explain_kill_or_die  function  is  used to call the kill(2) system call. On failure an explanation will be printed to stderr, obtained
       from the explain_kill(3) function, and then the process terminates by calling exit(EXIT_FAILURE).

       The explain_kill_on_error function is used to call the kill(2) system call. On failure an explanation will be printed to  stderr,  obtained
       from the explain_kill(3) function, but still returns to the caller.

       pid     The pid, exactly as to be passed to the kill(2) system call.

       sig     The sig, exactly as to be passed to the kill(2) system call.

RETURN VALUE

       The explain_kill_or_die function only returns on success, see kill(2) for more information. On failure, prints an explanation and exits, it
       does not return.

       The explain_kill_on_error function always returns the value return by the wrapped kill(2) system call.

EXAMPLE

       The explain_kill_or_die function is intended to be used in a fashion similar to the following example:
	      explain_kill_or_die(pid, sig);

SEE ALSO

       kill(2) send signal to a process

       explain_kill(3)
	       explain kill(2) errors

       exit(2) terminate the calling process

COPYRIGHT

       libexplain version 0.52
       Copyright (C) 2009 Peter Miller

															    explain_kill_or_die(3)