On Wed, Nov 3, 2010 at 8:42 AM, Brian Reichert <reich...@numachi.com> wrote: > On Tue, Nov 02, 2010 at 09:59:12PM -0400, Uri Guttman wrote: >> why are you concerned about closing the DATA handle? it is internal to >> the program. actually it is the handle the perl binary uses to read the >> source file and it is left at the seek point where the DATA starts. > > Because, I understand it to be best practice to close all file > handles, as per: > > http://www.webreference.com/perl/tutorial/9/2.html > > "Besides closing any filehandles that might have been opened ..." > > http://en.wikipedia.org/wiki/Daemon_%28computer_software%29 > > "Closing all inherited open files at the time of execution that > are left open by the parent process, ..." > > http://www.enderunix.org/docs/eng/daemon.php > > "Unneccesarry [sic] descriptors should be closed before fork() > system call (so that they are not inherited) or close all open > descriptors as soon as the child process starts running." > > I also have here in the office a copy of Steven's Unix Network > programming Volume 1, 2nd edition. Chapter 12 (Daemon Processes > and inetd SuperServer) describes daemonizing a process; his example > code lib/daemon_init.c also pointedly closes all file handles; review > that source here: > > http://www.kohala.com/start/unpv12e/unpv12e.tar.gz > > I'm maintaining a perl module (internally) that allows for convienent > daemonizing; I wrote it to be as 'correct' as possible.
What was wrong with the CPAN module Proc::Daemon? > Until yesterday, I didn't realize that DATA and END were magic file > descriptors in perl. As such, it would be easy to alter my module > to preserve them. If I can find reference to other magic descriptors, > then I'll take them into account as well. > >> well, perl keeps it open so it can be used by anyone reading from >> DATA. > > If it keeps it open (despite my closing the file descriptor), then > why does the daemonized process no longer have access to all of > it's contents? > >> this list (as most other rightly do) filters out attachments. so you >> should just paste your code in the email instead. > > That does make sense; I'll re-post soonish... > > Thanks for the feedback... > >> uri >> >> -- >> Uri Guttman ------ ...@stemsystems.com -------- http://www.sysarch.com -- >> ----- Perl Code Review , Architecture, Development, Training, Support ------ >> --------- Gourmet Hot Cocoa Mix ---- http://bestfriendscocoa.com --------- > > -- > Brian Reichert <reich...@numachi.com> > 55 Crystal Ave. #286 > Derry NH 03038-1725 USA BSD admin/developer at large > > _______________________________________________ > Boston-pm mailing list > Boston-pm@mail.pm.org > http://mail.pm.org/mailman/listinfo/boston-pm > _______________________________________________ Boston-pm mailing list Boston-pm@mail.pm.org http://mail.pm.org/mailman/listinfo/boston-pm
