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Postings from March 2002
> 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 __________________________________________________ Do You Yahoo!? Everything you'll ever need on one web page from News and Sport to Email and Music Charts http://uk.my.yahoo.comThread Previous