[linux-lvm] Writing forward compatible applications using /proc

Heinz J . Mauelshagen mauelshagen at sistina.com
Tue Aug 14 13:36:24 UTC 2001


On Tue, Aug 14, 2001 at 01:49:51AM +0200, Ragnar Kjørstad wrote:
> On Mon, Aug 13, 2001 at 10:08:58AM +0100, Joe Thornber wrote:
> > > Why will liblvm disappear? To me using a library interface seems much
> > > nicer than wrapping applications.
> > 
> > Because it's means there's yet another interface (along with the
> > command line tools, and ioctl's) to constrain any implementation
> > changes.  Command line tool interface will not change.  liblvm (if it
> > still existed as a shared library) will change drastically between 1.0
> > and 2.0 - not least because it in turn reflects the driver ioctl
> > interface.
> 
> I'm not complaining if it's changing, but if it's going away, that's bad
> :(
> 
> > The experimental branch has a single lvm tool, with liblvm statically
> > linked into it.  There's no need for the outside world to know about
> > liblvm.
> > 
> > It may be a good idea for Sistina to produce a tiny 'wrap the tools'
> > library for use by gui implementors.
> 
> yach! An uncomplete list of uglyness:
> * Errorhandling

Not much of a difference to the existing library error handling anyway.

> * fork/exec

Well, that's what the UNIX tool box is all about.
No mass fork/execs necessary.


> * having to format input arguments as strings (and quote them)

printf doesn't seem to hard to use ;-)

> * having to parse output data from strings 

No big deal with for eg. perl.

> 
> 
> -- 
> Ragnar Kjorstad
> Big Storage
> _______________________________________________
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> linux-lvm at sistina.com
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> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html

-- 

Regards,
Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

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Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen at Sistina.com                           +49 2626 141200
                                                       FAX 924446
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