Re: C++ File Lokcing

From	Nobody <nobody@nowhere.com>
Subject	Re: C++ File Lokcing
Date	2011-06-09 02:54 +0100
Message-Id	<pan.2011.06.09.01.54.16.875000@nowhere.com>
Newsgroups	comp.lang.c++
References	(2 earlier) <Linus-20110607083013@ram.dialup.fu-berlin.de> <islhj4$ajo$1@reader1.panix.com> <islhlo$u5n$1@dont-email.me> <islpuv$rhi$1@reader1.panix.com> <Xns9EFF26129EB0myfirstnameosapriee@216.196.109.131>
Organization	Zen Internet

Show all headers | View raw

On Wed, 08 Jun 2011 16:14:01 -0500, Paavo Helde wrote:

> On a multiuser OS one should not have many files writable by multiple
> users.

That isn't relevant to this thread. Locking is perfectly meaningful even
if a file is mode 0600 (-rw-------), only accessibly by a single user.

> For flock(), the lock is only advisory anyway, so all programs accessing
> the file must actively cooperate. These days much of the stuff is also
> NFS- mounted and flock() does not work there, so I would say it has only a
> very limited niche applicaton. No need to standardize something like that.

Locking is most useful for system processes, where you may have multiple
instances of a single program needing to perform concurrent access on a
shared file. Such files tend to live on the local drive (e.g. /var); NFS
is more common for /home and sometimes for /usr. If you want to put /var
onto NFS, you had better be using a fairly recent NFS version which
provides decent support for locking.

Back to comp.lang.c++ | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

C++ File Lokcing ruben safir <ruben@mrbrklyn.com> - 2011-06-06 22:41 +0000
  Re: C++ File Lokcing "osmium" <r124c4u102@comcast.net> - 2011-06-06 19:25 -0500
    Re: C++ File Lokcing Juha Nieminen <nospam@thanks.invalid> - 2011-06-07 06:25 +0000
    Re: C++ File Lokcing Öö Tiib <ootiib@hot.ee> - 2011-06-07 00:32 -0700
    Re: C++ File Lokcing ruben safir <ruben@mrbrklyn.com> - 2011-06-07 11:54 -0400
      Re: C++ File Lokcing Victor Bazarov <v.bazarov@comcast.invalid> - 2011-06-07 11:55 -0400
        Re: C++ File Lokcing Ruben Safir <ruben@mrbrklyn.com> - 2011-06-07 18:17 +0000
          Re: C++ File Lokcing Victor Bazarov <v.bazarov@comcast.invalid> - 2011-06-07 14:23 -0400
            Re: C++ File Lokcing Ruben Safir <ruben@mrbrklyn.com> - 2011-06-07 18:50 +0000
              Re: C++ File Lokcing Victor Bazarov <v.bazarov@comcast.invalid> - 2011-06-07 15:16 -0400
              Re: C++ File Lokcing Jeff Flinn <TriumphSprint2000@hotmail.com> - 2011-06-07 15:47 -0400
              Re: C++ File Lokcing Paavo Helde <myfirstname@osa.pri.ee> - 2011-06-07 15:04 -0500
                Re: C++ File Lokcing Ruben Safir <ruben@mrbrklyn.com> - 2011-06-07 22:46 +0000
                Re: C++ File Lokcing Nobody <nobody@nowhere.com> - 2011-06-08 07:50 +0100
                Re: C++ File Lokcing Sherm Pendley <sherm.pendley@gmail.com> - 2011-06-08 20:55 -0400
                Re: C++ File Lokcing Öö Tiib <ootiib@hot.ee> - 2011-06-08 18:33 -0700
              Re: C++ File Lokcing Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-06-08 07:43 +0000
            Re: C++ File Lokcing Nobody <nobody@nowhere.com> - 2011-06-07 21:21 +0100
          Re: C++ File Lokcing Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-06-08 07:21 +0000
          Re: C++ File Lokcing Paavo Helde <myfirstname@osa.pri.ee> - 2011-06-08 16:14 -0500
            Re: C++ File Lokcing drew@furrfu.invalid (Drew Lawson) - 2011-06-08 22:19 +0000
            Re: C++ File Lokcing Nobody <nobody@nowhere.com> - 2011-06-09 02:54 +0100

csiph-web