RE: nice, perl, fork and exec

thanks for that sample code. I added a little more to try it with multiple
child processes.
It turns out that the nice carries over to all the child processes on my
solaris box.

> -----Original Message-----
> From: Jonathan E. Paton [mailto:jonathanpaton@yahoo.com]
> Sent: Tuesday, March 19, 2002 1:28 PM
> To: beginners@perl.org
> Subject: Re: nice, perl, fork and exec
> 
> 
> > If I run a perl script with nice, (in Unix
> > it reprioritizes the process), and fork in
> > perl and run an exec "command" with the
> > child, does the nice priority apply to 
> > he child process also? and what about the
> > exec of the child process does it apply
> > there too?
> 
> IIRC...
> 
> Whenever you launch a child process, the child
> has the same permissions as the parent had/has.
> 
> For fork:
> 
> I know, that on Linux for the first time through
> the child shares the same timeslot with its
> parent.  I don't know, however, if that also
> applies to the next timeslots - it may be
> platform dependent.
> 
> For exec:
> 
> The process information (e.g. timeslot) applies
> as it did to the original.
> 
> > 
> > While we are on the subject, what about system()
> > and/or `` (backticks)?
> 
> system/`` creates a child process which Perl
> carefully arranges behind the scenes.  Perl blocks
> on these anyway whilst waiting for data, so you
> are unlikely to need to worry too much here.
> 
> > man nice didn't give me any information about
> > child processes.
> 
> man evil ;-)
> 
> > This is probably a perlcore developer type
> > question huh?
> 
> Not really, Perl implements stuff pretty much
> the way the C people do - who use libraries
> that show much of Unix's nasty guts in the APIs
> etc.
> 
> >  Or more likely a unix admin type question?
> 
> Definately.
> 
> > If so anyone know of a good unix mail list?
> 
> Have a wonder around:
> 
> www.linuxdoc.org
> 
> you may find something on this topic, if all
> else fails look for the glibc book (older book)
> which has the C interface for fork/exec etc.
> 
> Of course, you can check (and I recommend you
> do :) that I'm correct by doing something like:
> 
> #!/usr/bin/perl -w
> exec 'perl test.pl SLEEP' unless @ARGV;
> sleep 120; # Sleep 2 minutes
> 
> and starting it off with nice, then use ps.
> 
> Jonathan Paton
> 
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• nice, perl, fork and exec by Nikola Janceski
• RE: nice, perl, fork and exec by Richard Smith
• RE: nice, perl, fork and exec by Nikola Janceski
• Re: nice, perl, fork and exec by Jonathan E. Paton